title: Æthelstan

text: Like his father, Æthelstan was unwilling to marry his female relatives to his own subjects, so his sisters either entered nunneries or married foreign husbands. This was one reason for his close relations with European courts, and he married several of his half-sisters to European nobles in what historian Sheila Sharp called "a flurry of dynastic bridal activity unequalled again until Queen Victoria's time". Another reason lay in the common interest on both sides of the Channel in resisting the threat from the Vikings, while the rise in the power and reputation of the royal house of Wessex made marriage with an English princess more prestigious to European rulers. In 926 Hugh, Duke of the Franks, sent Æthelstan's cousin, Adelolf, Count of Boulogne, on an embassy to ask for the hand of one of Æthelstan's sisters. According to William of Malmesbury, the gifts Adelolf brought included spices, jewels, many swift horses, a crown of solid gold, the sword of Constantine the Great, Charlemagne's lance, and a piece of the Crown of Thorns. Æthelstan sent his half-sister Eadhild to be Hugh's wife.


title: Æthelstan

text: Æthelstan's most important European alliance was with the new Liudolfing dynasty in East Francia. The Carolingian dynasty of East Francia had died out in the early tenth century, and its new Liudolfing king, Henry the Fowler, was seen by many as an "arriviste". He needed a royal marriage for his son to establish his legitimacy, but no suitable Carolingian princesses were available. The ancient royal line of the West Saxons provided an acceptable alternative, especially as they (wrongly) claimed descent from the seventh-century king and saint, Oswald, who was venerated in Germany. In 929 or 930 Henry sent ambassadors to Æthelstan's court seeking a wife for his son, Otto, who later became Holy Roman Emperor. Æthelstan sent two of his half-sisters, and Otto chose Eadgyth. Fifty years later, Æthelweard, a descendant of Alfred the Great's older brother, addressed his Latin version of the "Anglo-Saxon Chronicle" to Mathilde, Abbess of Essen, who was Eadgyth's granddaughter, and had apparently requested it. The other sister, whose name is uncertain, was married to a prince from near the Alps who has not definitely been identified.


title: Æthelstan

text: In early medieval Europe, it was common for kings to act as foster-fathers for the sons of other kings. Æthelstan was known for the support he gave to dispossessed young royalty. In 936 he sent an English fleet to help his foster-son, Alan II, Duke of Brittany, to regain his ancestral lands, which had been conquered by the Vikings. In the same year he assisted the son of his half-sister Eadgifu, Louis, to take the throne of West Francia, and in 939 he sent another fleet that unsuccessfully attempted to help Louis in a struggle with rebellious magnates. According to later Scandinavian sources, he helped another possible foster-son, Hakon, son of Harald Fairhair, king of Norway, to reclaim his throne, and he was known among Norwegians as "Æthelstan the Good".


title: Æthelstan

text: Æthelstan's court was perhaps the most cosmopolitan of the Anglo-Saxon period. The close contacts between the English and European courts ended soon after his death, but descent from the English royal house long remained a source of prestige for continental ruling families. According to Frank Stenton in his history of the period, "Anglo-Saxon England", "Between Offa and Cnut there is no English king who played so prominent or so sustained a part in the general affairs of Europe."


title: Æthelstan

text: Foreign contemporaries described him in panegyrical terms. The French chronicler Flodoard described him as "the king from overseas", and the "Annals of Ulster" as the "pillar of the dignity of the western world". Some historians take a similar view. Michael Wood titled an essay, "The Making of King Aethelstan's Empire: an English Charlemagne?", and described him as "the most powerful ruler that Britain had seen since the Romans". In the view of Veronica Ortenberg, he was "the most powerful ruler in Europe" with an army that had repeatedly defeated the Vikings; continental rulers saw him as a Carolingian emperor, who "was clearly treated as the new Charlemagne". She wrote:


title: Æthelstan

text: Wessex kings carried an aura of power and success, which made them increasingly powerful in the 920s, while most Continental houses were in military trouble and engaged in internecine warfare. While the civil wars and the Viking attacks on the Continent had spelled the end of unity of the Carolingian empire, which had already disintegrated into separate kingdoms, military success had enabled Æthelstan to triumph at home and to attempt to go beyond the reputation of a great heroic dynasty of warrior kings, in order to develop a Carolingian ideology of kingship.


title: Æthelstan

text: Æthelstan died at Gloucester on 27 October 939. His grandfather Alfred, his father Edward, and his half-brother Ælfweard had been buried at Winchester, but Æthelstan chose not to honour the city associated with opposition to his rule. By his own wish, he was buried at Malmesbury Abbey, where he had buried his cousins who died at Brunanburh. No other member of the West Saxon royal family was buried there, and, according to William of Malmesbury, Æthelstan's choice reflected his devotion to the abbey and to the memory of its seventh-century abbot Saint Aldhelm. William described Æthelstan as fair-haired "as I have seen for myself in his remains, beautifully intertwined with gold threads". His bones were lost during the Reformation, but he is commemorated by an empty fifteenth-century tomb.


title: Æthelstan

text: After Æthelstan's death, the men of York immediately chose the Viking king of Dublin, Olaf Guthfrithson as their king, and Anglo-Saxon control of the north, seemingly made safe by the victory of Brunanburh, collapsed. The reigns of Æthelstan's half-brothers Edmund (939–946) and Eadred (946–955) were largely devoted to regaining control. Olaf seized the east midlands, leading to the establishment of a frontier at Watling Street. In 941 Olaf died, and Edmund took back control of the east midlands in 942, and then York in 944. Following Edmund's death York again switched back to Viking control, and it was only when the Northumbrians finally drove out their Norwegian Viking king Eric Bloodaxe in 954 and submitted to Eadred that Anglo-Saxon control of the whole of England was finally restored.


title: Æthelstan

text: Chronicle sources for the life of Æthelstan are limited, and the first biography, by Sarah Foot, was only published in 2011. The "Anglo-Saxon Chronicle" in Æthelstan's reign is principally devoted to military events, and it is largely silent apart from recording his most important victories. An important source is the twelfth-century chronicle of William of Malmesbury, but historians are cautious about accepting his testimony, much of which cannot be verified from other sources. David Dumville goes so far as to dismiss William's account entirely, regarding him as a "treacherous witness" whose account is unfortunately influential. However, Sarah Foot is inclined to accept Michael Wood's argument that William's chronicle draws on a lost life of Æthelstan. She cautions, however, that we have no means of discovering how far William "improved" on the original.


title: Æthelstan

text: In Dumville's view, Æthelstan has been regarded by historians as a shadowy figure because of an ostensible lack of source material, but he argues that the lack is more apparent than real. Charters, law codes, and coins throw considerable light on Æthelstan's government. The scribe known to historians as "Æthelstan A", who was responsible for drafting all charters between 928 and 935, provides very detailed information, including signatories, dates, and locations, illuminating Æthelstan's progress around his realm. "Æthelstan A" may have been Bishop Ælfwine of Lichfield, who was close to the king. By contrast with this extensive source of information, no charters survive from 910 to 924, a gap which historians struggle to explain, and which makes it difficult to assess the degree of continuity in personnel and the operation of government between the reigns of Edward and Æthelstan. Historians are also paying increasing attention to less conventional sources, such as contemporary poetry in his praise and manuscripts associated with his name.


title: Æthelstan

text: The reign of Æthelstan has been overshadowed by the achievements of his grandfather, Alfred the Great, but he is now considered one of the greatest kings of the West Saxon dynasty. Modern historians endorse the view of twelfth-century chronicler William of Malmesbury that "no one more just or more learned ever governed the kingdom". Frank Stenton and Simon Keynes both describe him as the one Anglo-Saxon king who will bear comparison with Alfred. In Keynes's view he "has long been regarded, with good reason, as a towering figure in the landscape of the tenth century ... he has also been hailed as the first king of England, as a statesman of international standing". David Dumville describes Æthelstan as "the father of mediaeval and modern England", while Michael Wood regards Offa, Alfred, and Æthelstan as the three greatest Anglo-Saxon kings, and Æthelstan as "one of the more important lay intellectuals in Anglo-Saxon history".


title: Æthelstan

text: Æthelstan is regarded as the first King of England by modern historians. Although it was his successors who would achieve the permanent conquest of Viking York, Æthelstan's campaigns made this success possible. His nephew Edgar called himself King of the English and revived the claim to rule over all the peoples of Britain. Simon Keynes argued that "the consistent usages of Edgar's reign represent nothing less than a determined reaffirmation of the polity created by Æthelstan in the 930s". Historian Charles Insley, however, sees Æthelstan's hegemony as fragile: "The level of overlordship wielded by Æthelstan during the 930s over the rest of Britain was perhaps not attained again by an English king until Edward I." George Molyneaux argues that:


title: Æthelstan

text: The tendency of some modern historians to celebrate Æthelstan as "the first king of England" is, however, problematic, since there is little sign that in his day the title "rex Anglorum" was closely or consistently tied to an area similar to that which we consider England. When Æthelstan's rule was associated with any definite geographical expanse, the territory in question was usually the whole island of Britain.


title: Æthelstan

text: Simon Keynes saw Æthelstan's law-making as his greatest achievement. His reign predates the sophisticated state of the later Anglo-Saxon period, but his creation of the most centralised government England had yet seen, with the king and his council working strategically to ensure acceptance of his authority and laws, laid the foundations on which his brothers and nephews would create one of the wealthiest and most advanced systems of government in Europe. Æthelstan's reign built upon his grandfather's ecclesiastical programme, consolidating the ecclesiastical revival and laying the foundation for the monastic reform movement later in the century.


title: Æthelstan

text: Æthelstan's reputation was at its height when he died. According to Sarah Foot, "He found acclaim in his own day not only as a successful military leader and effective monarch but also as a man of devotion, committed to the promotion of religion and the patronage of learning." Later in the century, Æthelweard praised him as a very mighty king worthy of honour, and Æthelred the Unready, who named his eight sons after his predecessors, put Æthelstan first as the name of his eldest son. In his biography of Æthelred, Levi Roach commented, "The king was clearly proud of his family and the fact that Æthelstan stands atop this list speaks volumes: though later overtaken by Alfred the Great in fame, in the 980s it must have seemed as if everything had begun with the king's great-uncle (a view with which many modern historians would be inclined to concur)."


title: Æthelstan

text: Memory of Æthelstan then declined until it was revived by William of Malmesbury, who took a special interest in him as the one king who had chosen to be buried in his own house. William's account kept his memory alive, and he was praised by other medieval chroniclers. In the early sixteenth century William Tyndale justified his English translation of the Bible by stating that he had read that King Æthelstan had caused the Holy Scriptures to be translated into Anglo-Saxon. From the sixteenth century onwards, Alfred's reputation became dominant, and Æthelstan largely disappeared from popular consciousness. Sharon Turner's "History of the Anglo-Saxons", first published between 1799 and 1805, played a crucial role in promoting Anglo-Saxon studies, and he helped to establish Brunanburh as a key battle in English history, but his treatment of Æthelstan was slight in comparison with Alfred. Charles Dickens had only one paragraph on Æthelstan in his "Child's History of England", and although Anglo-Saxon history was a popular subject for nineteenth-century artists, and Alfred was frequently depicted in paintings at the Royal Academy between 1769 and 1904, there was not one picture of Æthelstan.


title: Æthelstan

text: Williams comments: "If Æthelstan has not had the reputation which accrued to his grandfather, the fault lies in the surviving sources; Æthelstan had no biographer, and the "Chronicle" for his reign is scanty. In his own day he was 'the roof-tree of the honour of the western world'."


title: 4K resolution

text: 4K resolution refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 38402160 (4K UHD) is the dominant 4K standard, whereas the movie projection industry uses 40962160 (DCI 4K).


title: 4K resolution

text: The term "4K" is generic and refers to any resolution with a horizontal pixel count of approximately 4,000. Several different 4K resolutions have been standardized by various organizations.


title: 4K resolution

text: The terms "4K" and "Ultra HD" are used more widely in marketing than "2160p". While typically referring to motion pictures, some digital camera vendors have used the term "4K photo" for still photographs, making it appear like an especially high resolution even though 3840×2160 pixels equal approximately 8.3 megapixels, which is not considered to be especially high for still photographs.


title: 4K resolution

text: In 2005, Digital Cinema Initiatives (DCI), a prominent standards organization in the cinema industry, published the Digital Cinema System Specification. This specification establishes standardized 2K and 4K container formats for digital cinema production, with resolutions of and respectively. The resolution of the video content inside follows the SMPTE 428-1 standard, which establishes the following resolutions for a 4K distribution:


title: 4K resolution

text: 2K distributions can have a frame rate of either 24 or 48FPS, while 4K distributions must have a frame rate of 24FPS.


title: 4K resolution

text: Some articles claim that the terms "2K" and "4K" were coined by DCI and refer exclusively to the 2K and 4K formats defined in the DCI standard. However, usage of these terms in the cinema industry predates the publication of the DCI standard, and they are generally understood as casual terms for any resolution approximately 2000 or 4000 pixels in width, rather than names for specific resolutions.


title: 4K resolution

text: In 2007, the Society of Motion Picture and Television Engineers published SMPTE ST 2036-1, which defines parameters for two UHDTV systems called UHDTV1 and UHDTV2. The standard defines the following characteristics for these systems:


title: 4K resolution

text: In 2012, the International Telecommunication Union, Radiocommunication Sector published Recommendation ITU-R BT.2020, also known as the Ultra High Definition Television (UHDTV) standard. It adopts the same image parameters defined in SMPTE ST 2036–1.


title: 4K resolution

text: Although the UHDTV standard does not define any official names for the formats it defines, ITU typically uses the terms "4K", "4K UHD", or "4K UHDTV" to refer to the system in public announcements and press releases ("8K" for the system). In some of ITU's other standards documents, the terms "UHDTV1" and "UHDTV2" are used as shorthand.


title: 4K resolution

text: In October 2012, the Consumer Electronics Association (CEA) announced their definition of the term Ultra High-Definition (or Ultra HD) for use with marketing consumer display devices. CEA defines an "Ultra HD" product as a TV, monitor, or projector with the following characteristics:


title: 4K resolution

text: The CEA definition does allow manufacturers to use other terms—such as "4K"—alongside the Ultra HD logo. Since the resolution in CEA's definition is only a minimum requirement, displays with higher resolutions such as or also qualify as "Ultra HD" displays, provided they meet the other requirements.


title: 4K resolution

text: Some 4K resolutions, like , are often casually referred to as "2160p". This name follows from the previous naming convention used by HDTV and SDTV formats, which refer to a format by the number of pixels/lines along the vertical axis (such as "1080p" for progressive scan, or "480i" for the 480-line interlaced SDTV formats) rather than the horizontal pixel count (≈4000 or "4K" for ).


title: 4K resolution

text: The term "2160p" could be applied to any format with a height of 2160 pixels, but it is most commonly used in reference to the 4K UHDTV resolution of due to its association with the well-known 720p and 1080p HDTV formats. Although is both a 4K resolution and a 2160p resolution, these terms cannot always be used interchangeably since not all 4K resolutions are 2160 pixels tall, and not all 2160p resolutions are ≈4000 pixels wide. However, some companies have begun using the term "4K" to describe devices with support for a 2160p resolution, even if it is not close to 4000 pixels wide. For example, many "4K" dash cams only support a resolution of (43); although this is a 2160p resolution, it is not a 4K resolution. Conversely, Samsung released a () TV, but marketed it as a "4K" TV despite its 5K-class resolution.


title: 4K resolution

text: In 2015, LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology. The media and internet users later called this "RGBW" TVs because of the white sub pixel.


title: 4K resolution

text: Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. After tests done by Intertek in which the technical aspects of LG M+ TVs were analyzed and they concluded that "the addressable resolution display is 2,880 X 2,160 for each red, green, blue", in other words, the LG TVs were technically 2.8K as it became known in the controversy. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it is more popular in the TV market due to the supposed 4K UHD marketed resolution but still being incapable of achieving true 4K UHD resolution as defined by the CTA as 3840x2160 active pixels with 8-bit per color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.


title: 4K resolution

text: In 2019, Sony was granted the CinemaWide trademark by the European Union Intellectual Property Office (EUIPO), in which the trademark covers 'Class 9' electronic devices, including smartphones. According to Sony and SID, the standard defines a CinemaWide 4K product with the following characteristics:


title: 4K resolution

text: Sony Xperia smartphones are the most widely known products that equipped with CinemaWide 4K display, such as Xperia 1, Xperia 1 II and Xperia 1 III.


title: 4K resolution

text: Video sharing website YouTube and the television industry have adopted 38402160 as their 4K standard. , 4K content from major broadcasters remained limited. On April 11, 2013, Bulb TV created by Canadian serial entrepreneur Evan Kosiner became the first broadcaster to provide a 4K linear channel and VOD content to cable and satellite companies in North America. The channel is licensed by the Canadian Radio-Television and Telecommunications Commission to provide educational content. However, 4K content is becoming more widely available online including on Apple TV, YouTube, Netflix, Hulu, and Amazon. By 2013, some UHDTV models were available to general consumers in the range of US$600. , prices on smaller computer and television panels had dropped below US$400.


title: 4K resolution

text: On March 26, 2013, the Advanced Television Systems Committee announced new proposals of a new standard called ATSC 3.0 which would implement UHD broadcasts at resolutions of up to or . The standard would also include framerates of up to 120Hz, HEVC encoding, wide color gamut, as well as high dynamic range.


title: 4K resolution

text: In 2014, the Digital Video Broadcasting Project released a new set of standards intended to guide the implementation of high resolution content in broadcast television. Dubbed DVB-UHDTV, it establishes two standards, known as UHD-1 (for 4K content) and UHD-2 (for 8K content). These standards use resolutions of 38402160 and 76804320 respectively, with framerates of up to 60Hz, color depth up to 10bpc (30bit/px), and HEVC encoding for transmission. DVB is currently focusing on the implementation of the UHD-1 standard.


title: 4K resolution

text: DVB finalized UHD-1 Phase 2 in 2016, with the introduction of service by broadcasters expected in 2017. UHD-1 Phase 2 adds features such as high dynamic range (using HLG and PQ at 10 or 12 bits), wide color gamut (BT. 2020/2100 colorimetry), and high frame rate (up to 120Hz).


title: 4K resolution

text: YouTube, since 2010, and Vimeo allow a maximum upload resolution of 4096 × 3072 pixels (12.6 megapixels, aspect ratio 4:3). Vimeo's 4K content is currently limited to mostly nature documentaries and tech coverage.


title: 4K resolution

text: High Efficiency Video Coding (HEVC or H.265) should allow streaming 4K content with a bandwidth of 20 to 30 Mbit/s.


title: 4K resolution

text: The first mobile phones to be able to record at 2160p () were released in late 2013, including the Samsung Galaxy Note 3, which is able to record 2160p at 30 frames per second.


title: 4K resolution

text: In the year 2014, the OnePlus One was released with the option to record DCI 4K () at 24 frames per second, as well as LG G3 and Samsung Galaxy Note 4 with optical image stabilization.


title: 4K resolution

text: In the year 2015, Apple announced the iPhone 6s was released with the 12megapixel camera that has the option to record 4K at 25 or 30 frames per second.


title: 4K resolution

text: In the years 2017 and 2018, mobile phone chipsets reached sufficient processing power that mobile phone vendors started releasing mobile phones that allow recording 2160p footage at 60 frames per second for a smoother and more realistic appearance.


title: 4K resolution

text: In 1984, Hitachi released the CMOS graphics processor ARTC HD63484, which was capable of displaying up to 4K resolution when in monochrome mode. The resolution was targeted at the bit-mapped desktop publishing market. The first commercially available 4K camera for cinematographic purposes was the Dalsa Origin, released in 2003. 4K technology was developed by several research groups in universities around the world, such as University of California, San Diego, CALIT2, Keio University, Naval Postgraduate School and others that realized several demonstrations in venues such as IGrid in 2004 and CineGrid. YouTube began supporting 4K for video uploads in 2010 as a result of leading manufacturers producing 4K cameras. Users could view 4K video by selecting "Original" from the quality settings until December 2013, when the 2160p option appeared in the quality menu. In November 2013, YouTube began to use the VP9 video compression standard, saying that it was more suitable for 4K than High Efficiency Video Coding (HEVC). Google, which owns YouTube, developed VP9.


title: 4K resolution

text: Theaters began projecting movies at 4K resolution in 2011. Sony was offering 4K projectors as early as 2004. The first 4K home theater projector was released by Sony in 2012. Despite this, few finished films have 4K resolution as of 2019. Even for movies and TV shows shot using 6K or 8K cameras, almost all finished films are edited in HD resolution and enlarged to fit a 4K format.


title: 4K resolution

text: Sony is one of the leading studios promoting UHDTV content, offering a little over 70 movie and television titles via digital download to a specialized player that stores and decodes the video. The large files (≈40GB), distributed through consumer broadband connections, raise concerns about data caps.


title: 4K resolution

text: In 2014, Netflix began streaming "House of Cards", "Breaking Bad", and "some nature documentaries" at 4K to compatible televisions with an HEVC decoder. Most 4K televisions sold in 2013 did not natively support HEVC, with most major manufacturers announcing support in 2014. Amazon Studios began shooting their full-length original series and new pilots with 4K resolution in 2014. They are now currently available though Amazon Video.


title: 4K resolution

text: In March 2016 the first players and discs for Ultra HD Blu-ray—a physical optical disc format supporting 4K resolution and high-dynamic-range video (HDR) at 60 frames per second—were released.


title: 4K resolution

text: On August 2, 2016, Microsoft released the Xbox One S, which supports 4K streaming and has an Ultra HD Blu-ray disc drive, but does not support 4K gaming. On November 10, 2016, Sony released the PlayStation 4 Pro, which supports 4K streaming and gaming, though many games use checkerboard rendering or are upscaled 4K. On November 7, 2017, Microsoft released the Xbox One X, which supports of 4K streaming and gaming, though not all games are rendered at native 4K.


title: 4K resolution

text: Though experiencing rapid price drops beginning in 2013 for viewing devices, the home cinema digital video projector market saw little expansion, with only a few manufacturers (only Sony ) offering limited 4K-capable lineups, with native 4K projectors commanding five-figure price tags well into 2015 before finally breaking the US$10,000 barrier. Critics state that at normal direct-view panel size and viewing distances, the extra pixels of 4K are redundant at the ability of normal human vision. Projection home cinemas, on the other hand, employ much larger screen sizes without necessarily increasing viewing distance to scale. JVC has used a technique known as "e-shift" to extrapolate extra pixels from 1080p sources to display 4K on screens through upscaling or from native 4K sources at a much lower price than native 4K projectors. This technology of non-native 4K entered its fourth generation for 2016. JVC used this same technology to provide 8K flight simulation for Boeing that met the limits of 20/25 visual acuity.


title: 4K resolution

text: Pixel shifting, as described here, was pioneered in the consumer space by JVC, and later in the commercial space by Epson. That said, it is not the same thing as "true" 4K. More recently, some DLP projectors claim 4K UHD (which the JVCs and Epsons do not claim).


title: 4K resolution

text: As noted above, DCI 4K is 40962160, while 4K UHD is 38402160, producing a slight difference in aspect ratio rather than a significant difference in resolution. Traditional displays, such as LCD or OLED, are 3840 pixels across the screen, with each pixel being 1/3840th of the screen width. They do not overlap—if they did, they would suffer reduced detail. The diameter of each pixel is basically 1/3840th of the screen width or 1/2160th of the screen height - either gives the same size pixel. That 38402160 works out to 8.3 megapixels, the official resolution of 4K UHD (and therefore Blu-ray UHD discs).


title: 4K resolution

text: The 4K UHD standard does not specify how large the pixels are, so a 4K UHD projector (Optoma, BenQ, Dell, et al.) counts because these projectors have a 2718 × 1528 pixel structure. Those projectors process the true 4K of data and project it with overlapping pixels, which is what pixel shifting is. Unfortunately, each of those pixels is far larger: each one has 50% more area than true 4K. Pixel shifting projectors project a pixel, shift it up to the right, by a half diameter, and project it again, with modified data, but that second pixel overlaps the first.


title: 4K resolution

text: In other words, pixel shifting cannot produce adjacent vertical lines of RGBRGB or other colors where each line is one pixel (1/3840th of the screen) wide. Adjacent red and green pixels would end up looking like yellow, with a fringe on one side of red, on the other of green - except that the next line of pixels overlaps as well, changing the color of that fringe. 4K UHD or 1080p pixel shifting cannot reveal the fine detail of a true 4K projector such as those Sony ships (business, education and home markets). Also, JVC has one true 4K projector priced at $35,000 (as of mid-2017).


title: 4K resolution

text: So while 4K UHD appears like it has a pixel structures with 1/4 the area of 1080p, that does not happen with pixel shifting. Only a true 4K projector offers that level of resolution. This is why "true" 4K projectors cost so much more than 4K UHD projectors with otherwise similar feature sets. They produce smaller pixels, finer resolution, no compromising of detail or color from overlapping pixels. By comparison, the slight difference in aspect ratio between DCI and 3840 × 2160 pixel displays without overlap is insignificant relative to the amount of detail.


title: 4K resolution

text: Some companies like Kaleidescape offer media servers that allow for 4K UHD Blu-ray movies with high dynamic range in a home theater.


title: 4K resolution

text: In November 2014, United States satellite provider DirecTV became the first pay TV provider to offer access to 4K content, although limited to selected video-on-demand films. In August 2015, British sports network BT Sport launched a 4K feed, with its first broadcast being the 2015 FA Community Shield football match. Two production units were used, producing the traditional broadcast in high-definition, and a separate 4K broadcast. As the network did not want to mix 4K footage with upconverted HD footage, this telecast did not feature traditional studio segments at pre-game or half-time, but those hosted from the stadium by the match commentators using a 4K camera. BT envisioned that if viewers wanted to watch studio analysis, they would switch to the HD broadcast and then back for the game. Footage was compressed using H.264 encoders and transmitted to BT Tower, where it was then transmitted back to BT Sport studios and decompressed for distribution, via 4K-compatible BT TV set-top boxes on an eligible BT Infinity internet plan with at least a 25 Mbit/s connection.


title: 4K resolution

text: In late 2015 and January 2016, three Canadian television providers including Quebec-based Vidéotron, Ontario-based Rogers Cable, and Bell Fibe TV, announced that they would begin to offer 4K compatible set-top boxes that can stream 4K content to subscribers over gigabit internet service. On October 5, 2015, alongside the announcement of its 4K set-top box and gigabit internet, Canadian media conglomerate Rogers Communications announced that it planned to produce 101 sports telecasts in 4K in 2016 via its Sportsnet division, including all Toronto Blue Jays home games, and "marquee" National Hockey League games beginning in January 2016. Bell Media announced via its TSN division a slate of 4K telecasts to begin on January 20, 2016, including selected Toronto Raptors games and regional NHL games.


title: 4K resolution

text: On January 14, 2016, in cooperation with BT Sport, Sportsnet broadcast the first ever NBA game produced in 4K a Toronto Raptors/Orlando Magic game at O2 Arena in London, England. On January 20, also during a Raptors game, TSN presented the first live 4K telecast produced in North America. Three days later, Sportsnet presented the first NHL game in 4K.


title: 4K resolution

text: Dome Productions, a joint venture of Bell Media and Rogers Media (the respective owners of TSN and Sportsnet), constructed a "side-by-side" 4K mobile production unit shared by Sportsnet and TSN's first 4K telecasts; it was designed to operate alongside a separate HD truck and utilize cameras capable of output in both formats. For the opening game of the 2016 Toronto Blue Jays season, Dome constructed "Trillium" a production truck integrating both 4K and 1080i high-definition units. Bell Media's CTV also broadcast the 2016 Juno Awards in 4K as the first awards show presented in the format.


title: 4K resolution

text: In February 2016, Univision trialed 4K by producing a closed circuit telecast of a football friendly between the national teams of Mexico and Senegal from Miami in the format. The broadcast was streamed privately to several special viewing locations. Univision aimed to develop a 4K streaming app to publicly televise the final of Copa América Centenario in 4K. In March 2016, DirecTV and CBS Sports announced that they would produce the "Amen Corner" supplemental coverage from the Masters golf tournament in 4K.


title: 4K resolution

text: After having trialed the technology in limited matches at the 2013 FIFA Confederations Cup, and the 2014 FIFA World Cup (via private tests and public viewings in the host city of Rio de Janeiro), the 2018 FIFA World Cup was the first FIFA World Cup in which all matches were produced in 4K. Host Broadcasting Services stated that at least 75% of the broadcast cut on each match would come from 4K cameras (covering the majority of main angles), with instant replays and some camera angles being upconverted from 1080p sources. These broadcasts were made available from selected rightsholders, such as the BBC in the United Kingdom, and selected television providers in the United States.


title: 4K resolution

text: The resolution of is the dominant 4K resolution in the consumer media and display industries. This is the resolution of the UHDTV1 format defined in SMPTE ST 2036–1, as well as the 4K UHDTV format defined by ITU-R in Rec. 2020, and is also the minimum resolution for CEA's definition of "Ultra HD" displays and projectors. The resolution of was also chosen by the DVB project for their 4K broadcasting standard, UHD-1.


title: 4K resolution

text: This resolution has an aspect ratio of 169, with 8,294,400 total pixels. It is exactly double the horizontal and vertical resolution of 1080p () for a total of 4 times as many pixels, and triple the horizontal and vertical resolution of 720p () for a total of 9 times as many pixels. It is sometimes referred to as "2160p", based on the naming patterns established by the previous 720p and 1080p HDTV standards.


title: 4K resolution

text: In 2013, televisions capable of displaying UHD resolutions were seen by consumer electronics companies as the next trigger for an upgrade cycle after a lack of consumer interest in 3D television.


title: 4K resolution

text: This resolution is used mainly in digital cinema production, and has a total of 8,847,360 pixels with an aspect ratio of 256135 (≈1910). It was standardized as the resolution of the 4K container format defined by Digital Cinema Initiatives in the Digital Cinema System specification, and is the native resolution of all DCI-compliant 4K digital projectors and monitors. The DCI specification allows several different resolutions for the content inside the container, depending on the desired aspect ratio. The allowed resolutions are defined in SMPTE 428-1:


title: 4K resolution

text: The DCI 4K standard has twice the horizontal and vertical resolution of DCI 2K (), with four times as many pixels overall.


title: 4K resolution

text: Digital movies made in 4K may be produced, scanned, or stored in a number of other resolutions depending on what storage aspect ratio is used. In the digital cinema production chain, a resolution of 4096 × 3112 is often used for acquiring "open gate" or anamorphic input material, a resolution based on the historical resolution of scanned Super 35 mm film.


title: 4K resolution

text: The main advantage of recording video at the 4K standard is that fine spatial detail is resolved well. Individual still frames extracted from 3840×2160-pixel video footage can act as 8.3 megapixel still photographs, while only 2.1 megapixels at 1080p and 0.9 megapixels at 720p. If the final video quality is reduced to 2K from a 4K recording, more detail is apparent than would have been achieved from a native 2K recording. Increased fineness and contrast is then possible with output to DVD and Blu-ray. Some cinematographers record at 4K with the Super 35 film format to offset any resolution loss that may occur during video processing.


title: 4K resolution

text: Many consumer electronics such as mobile phones store video footage in format with 4:2:0 chroma subsampling, which records color information at only one quarter the resolution as the brightness information. For video, this means that the color information is only stored at .


title: 4K resolution

text: Consumer cameras and mobile phones record 2160p footage at much higher bit rates (usually 50 to 100Mbit/s) than 1080p (usually 10 to 30Mbit/s). This higher bit rate reduces the visibility of compression artifacts, even if viewed on monitors with a lower resolution than 2160p.


title: Yellowstone National Park

text: Yellowstone National Park is an American national park located in the western United States, largely in the northwest corner of Wyoming and extending into Montana and Idaho. It was established by the 42nd U.S. Congress with the Yellowstone National Park Protection Act and signed into law by President Ulysses S. Grant on March 1, 1872. Yellowstone was the first national park in the U.S. and is also widely held to be the first national park in the world. The park is known for its wildlife and its many geothermal features, especially the Old Faithful geyser, one of its most popular. While it represents many types of biomes, the subalpine forest is the most abundant. It is part of the South Central Rockies forests ecoregion.


title: Yellowstone National Park

text: While Native Americans have lived in the Yellowstone region for at least 11,000 years, aside from visits by mountain men during the early-to-mid-19th century, organized exploration did not begin until the late 1860s. Management and control of the park originally fell under the jurisdiction of the United States Department of the Interior, the first Secretary of the Interior to supervise the park being Columbus Delano. However, the U.S. Army was eventually commissioned to oversee management of Yellowstone for a 30-year period between 1886 and 1916. In 1917, administration of the park was transferred to the National Park Service, which had been created the previous year. Hundreds of structures have been built and are protected for their architectural and historical significance, and researchers have examined more than a thousand archaeological sites.


title: Yellowstone National Park

text: Yellowstone National Park spans an area of , comprising lakes, canyons, rivers, and mountain ranges. Yellowstone Lake is one of the largest high-elevation lakes in North America and is centered over the Yellowstone Caldera, the largest supervolcano on the continent. The caldera is considered a dormant volcano. It has erupted with tremendous force several times in the last two million years. Well over half of the world's geysers and hydrothermal features are in Yellowstone, fueled by this ongoing volcanism. Lava flows and rocks from volcanic eruptions cover most of the land area of Yellowstone. The park is the centerpiece of the Greater Yellowstone Ecosystem, the largest remaining nearly-intact ecosystem in the Earth's northern temperate zone. In 1978, Yellowstone was named a UNESCO World Heritage Site.


title: Yellowstone National Park

text: Hundreds of species of mammals, birds, fish, reptiles, and amphibians have been documented, including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Yellowstone Park is the largest, and most famous megafauna location in the contiguous United States. Grizzly bears, wolves, and free-ranging herds of bison and elk live in this park. The Yellowstone Park bison herd is the oldest and largest public bison herd in the United States. Forest fires occur in the park each year; in the large forest fires of 1988, nearly one third of the park was burnt. Yellowstone has numerous recreational opportunities, including hiking, camping, boating, fishing, and sightseeing. Paved roads provide close access to the major geothermal areas as well as some of the lakes and waterfalls. During the winter, visitors often access the park by way of guided tours that use either snow coaches or snowmobiles.


title: Yellowstone National Park

text: The park contains the headwaters of the Yellowstone River, from which it takes its historical name. Near the end of the 18th century, French trappers named the river ', which is probably a translation of the Hidatsa name ' ("Yellow Stone River"). Later, American trappers rendered the French name in English as "Yellow Stone". Although it is commonly believed that the river was named for the yellow rocks seen in the Grand Canyon of the Yellowstone, the Native American name source is unclear.


title: Yellowstone National Park

text: The human history of the park began at least 11,000 years ago when Native Americans began to hunt and fish in the region. During the construction of the post office in Gardiner, Montana, in the 1950s, an obsidian point of Clovis origin was found that dated from approximately 11,000 years ago. These Paleo-Indians, of the Clovis culture, used the significant amounts of obsidian found in the park to make cutting tools and weapons. Arrowheads made of Yellowstone obsidian have been found as far away as the Mississippi Valley, indicating that a regular obsidian trade existed between local tribes and tribes farther east. When the Lewis and Clark Expedition entered present-day Montana in 1805 they encountered the Nez Perce, Crow, and Shoshone tribes who described to them the Yellowstone region to the south, but they chose not to investigate.


title: Yellowstone National Park

text: In 1806, John Colter, a member of the Lewis and Clark Expedition, left to join a group of fur trappers. After splitting up with the other trappers in 1807, Colter passed through a portion of what later became the park, during the winter of 1807–1808. He observed at least one geothermal area in the northeastern section of the park, near Tower Fall. After surviving wounds he suffered in a battle with members of the Crow and Blackfoot tribes in 1809, Colter described a place of "fire and brimstone" that most people dismissed as delirium; the supposedly mystical place was nicknamed "Colter's Hell". Over the next 40 years, numerous reports from mountain men and trappers told of boiling mud, steaming rivers, and petrified trees, yet most of these reports were believed at the time to be myth.


title: Yellowstone National Park

text: After an 1856 exploration, mountain man Jim Bridger (also believed to be the first or second European American to have seen the Great Salt Lake) reported observing boiling springs, spouting water, and a mountain of glass and yellow rock. These reports were largely ignored because Bridger was a known "spinner of yarns". In 1859, a U.S. Army Surveyor named Captain William F. Raynolds embarked on a two-year survey of the southern central Rockies. After wintering in Wyoming, in May 1860, Raynolds and his party—which included geologist Ferdinand V. Hayden and guide Jim Bridger—attempted to cross the Continental Divide over Two Ocean Plateau from the Wind River drainage in northwest Wyoming. Heavy spring snows prevented their passage, but had they been able to traverse the divide, the party would have been the first organized survey to enter the Yellowstone region. The American Civil War hampered further organized explorations until the late 1860s.


title: Yellowstone National Park

text: The first detailed expedition to the Yellowstone area was the Cook–Folsom–Peterson Expedition of 1869, which consisted of three privately funded explorers. The Folsom party followed the Yellowstone River to Yellowstone Lake. The members of the Folsom party kept a journal, and based on the information it reported, a party of Montana residents organized the Washburn–Langford–Doane Expedition in 1870. It was headed by the surveyor-general of Montana Henry Washburn, and included Nathaniel P. Langford (who later became known as "National Park" Langford) and a U.S. Army detachment commanded by Lt. Gustavus Doane. The expedition spent about a month exploring the region, collecting specimens and naming sites of interest.


title: Yellowstone National Park

text: A Montana writer and lawyer named Cornelius Hedges, who had been a member of the Washburn expedition, proposed that the region should be set aside and protected as a national park; he wrote detailed articles about his observations for the "Helena Herald" newspaper between 1870 and 1871. Hedges essentially restated comments made in October 1865 by acting Montana Territorial Governor Thomas Francis Meagher, who had previously commented that the region should be protected. Others made similar suggestions. An 1871 letter to Ferdinand V. Hayden from Jay Cooke, a businessman who wanted to bring tourists to the region, encouraged him to mention it in his official report of the survey. Cooke wrote that his friend, Congressman William D. Kelley had also suggested "Congress pass a bill reserving the Great Geyser Basin as a public park forever".


title: Yellowstone National Park

text: In 1871, eleven years after his failed first effort, Ferdinand V. Hayden was finally able to explore the region. With government sponsorship, he returned to the region with a second, larger expedition, the Hayden Geological Survey of 1871. He compiled a comprehensive report, including large-format photographs by William Henry Jackson and paintings by Thomas Moran. The report helped to convince the U.S. Congress to withdraw this region from public auction. On March 1, 1872, President Ulysses S. Grant signed "The Act of Dedication" law that created Yellowstone National Park.


title: Yellowstone National Park

text: Hayden, while not the only person to have thought of creating a park in the region, was its first and most enthusiastic advocate. He believed in "setting aside the area as a pleasure ground for the benefit and enjoyment of the people" and warned that there were those who would come and "make merchandise of these beautiful specimens". Worrying the area could face the same fate as Niagara Falls, he concluded the site should "be as free as the air or Water." In his report to the Committee on Public Lands, he concluded that if the bill failed to become law, "the vandals who are now waiting to enter into this wonder-land, will in a single season despoil, beyond recovery, these remarkable curiosities, which have required all the cunning skill of nature thousands of years to prepare".


title: Yellowstone National Park

text: Hayden and his 1871 party recognized Yellowstone as a unique place that should be available for further research. He also was encouraged to preserve it for others to see and experience it as well. In 1873, Congress authorized and funded a survey to find a wagon route to the park from the south which was completed by the Jones Expedition of 1873. Eventually the railroads and, some time after that, the automobile would make that possible. The park was not set aside strictly for ecological purposes; however, the designation "pleasure ground" was not an invitation to create an amusement park. Hayden imagined something akin to the scenic resorts and baths in England, Germany, and Switzerland.


title: Yellowstone National Park

text: There was considerable local opposition to the Yellowstone National Park during its early years. Some of the locals feared that the regional economy would be unable to thrive if there remained strict federal prohibitions against resource development or settlement within park boundaries and local entrepreneurs advocated reducing the size of the park so that mining, hunting, and logging activities could be developed. To this end, numerous bills were introduced into Congress by Montana representatives who sought to remove the federal land-use restrictions.


title: Yellowstone National Park

text: After the park's official formation, Nathaniel Langford was appointed as the park's first superintendent in 1872 by Secretary of Interior Columbus Delano, the first overseer and controller of the park. Langford served for five years but was denied a salary, funding, and staff. Langford lacked the means to improve the land or properly protect the park, and without formal policy or regulations, he had few legal methods to enforce such protection. This left Yellowstone vulnerable to poachers, vandals, and others seeking to raid its resources. He addressed the practical problems park administrators faced in the 1872 Report to the Secretary of the Interior and correctly predicted that Yellowstone would become a major international attraction deserving the continuing stewardship of the government. In 1874, both Langford and Delano advocated the creation of a federal agency to protect the vast park, but Congress refused. In 1875, Colonel William Ludlow, who had previously explored areas of Montana under the command of George Armstrong Custer, was assigned to organize and lead an expedition to Montana and the newly established Yellowstone Park. Observations about the lawlessness and exploitation of park resources were included in Ludlow's "Report of a Reconnaissance to the Yellowstone National Park". The report included letters and attachments by other expedition members, including naturalist and mineralogist George Bird Grinnell.


title: Yellowstone National Park

text: Grinnell documented the poaching of buffalo, deer, elk, and antelope for hides. "It is estimated that during the winter of 1874–1875, not less than 3,000 buffalo and mule deer suffer even more severely than the elk, and the antelope nearly as much."


title: Yellowstone National Park

text: Having traveled through Yellowstone and witnessed land management problems first hand, Philetus Norris volunteered for the position following Langford's exit. Congress finally saw fit to implement a salary for the position, as well as to provide minimal funding to operate the park. Norris used these funds to expand access to the park, building numerous crude roads and facilities.


title: Yellowstone National Park

text: In 1880, Harry Yount was appointed as a gamekeeper to control poaching and vandalism in the park. Yount had previously spent decades exploring the mountain country of present-day Wyoming, including the Grand Tetons, after joining F V. Hayden's Geological Survey in 1873. Yount is the first national park ranger, and Yount's Peak, at the head of the Yellowstone River, was named in his honor. However, these measures still proved to be insufficient in protecting the park, as neither Norris, nor the three superintendents who followed, were given sufficient manpower or resources.


title: Yellowstone National Park

text: The Northern Pacific Railroad built a train station in Livingston, Montana, connecting to the northern entrance in the early 1880s, which helped to increase visitation from 300 in 1872 to 5,000 in 1883. A line was also extended from Livingston to Gardiner station, where passengers switched to stagecoach. Visitors in these early years faced poor roads and limited services, and most access into the park was on horse or via stagecoach. By 1908 visitation increased enough to attract a Union Pacific Railroad connection to West Yellowstone, though rail visitation fell off considerably by World War II and ceased around the 1960s. Much of the railroad line was converted to nature trails, among them the Yellowstone Branch Line Trail.


title: Yellowstone National Park

text: During the 1870s and 1880s, Native American tribes were effectively excluded from the national park. Under a half-dozen tribes had made seasonal use of the Yellowstone area- the only year-round residents were small bands of Eastern Shoshone known as "Sheepeaters". They left the area under the assurances of a treaty negotiated in 1868, under which the Sheepeaters ceded their lands but retained the right to hunt in Yellowstone. The United States never ratified the treaty, and refused to recognize the claims of the Sheepeaters or any other tribe that had used Yellowstone.


title: Yellowstone National Park

text: The Nez Perce band associated with Chief Joseph, numbering about 750 people, passed through Yellowstone National Park in thirteen days during late August 1877. They were being pursued by the U.S. Army and entered the national park about two weeks after the Battle of the Big Hole. Some of the Nez Perce were friendly to the tourists and other people they encountered in the park; some were not. Nine park visitors were briefly taken captive. Despite Joseph and other chiefs ordering that no one should be harmed, at least two people were killed and several wounded. One of the areas where encounters occurred was in Lower Geyser Basin and east along a branch of the Firehole River to Mary Mountain and beyond. That stream is still known as Nez Perce Creek. A group of Bannocks entered the park in 1878, alarming park Superintendent Philetus Norris. In the aftermath of the Sheepeater Indian War of 1879, Norris built a fort to prevent Native Americans from entering the national park.


title: Yellowstone National Park

text: Ongoing poaching and destruction of natural resources continued unabated until the U.S. Army arrived at Mammoth Hot Springs in 1886 and built Camp Sheridan. Over the next 22 years, as the army constructed permanent structures, Camp Sheridan was renamed Fort Yellowstone. On May 7, 1894, the Boone and Crockett Club, acting through the personality of George G. Vest, Arnold Hague, William Hallett Phillips, W. A. Wadsworth, Archibald Rogers, Theodore Roosevelt, and George Bird Grinnell were successful in carrying through the Park Protection Act, which saved the park. The Lacey Act of 1900 provided legal support for the officials prosecuting poachers. With the funding and manpower necessary to keep a diligent watch, the army developed their own policies and regulations that permitted public access while protecting park wildlife and natural resources. When the National Park Service was created in 1916, many of the management principles developed by the army were adopted by the new agency. The army turned control over to the National Park Service on October 31, 1918.


title: Yellowstone National Park

text: In 1898, the naturalist John Muir described the park as follows: "However orderly your excursions or aimless, again and again amid the calmest, stillest scenery you will be brought to a standstill hushed and awe-stricken before phenomena wholly new to you. Boiling springs and huge deep pools of purest green and azure water, thousands of them, are plashing and heaving in these high, cool mountains as if a fierce furnace fire were burning beneath each one of them; and a hundred geysers, white torrents of boiling water and steam, like inverted waterfalls, are ever and anon rushing up out of the hot, black underworld."


title: Yellowstone National Park

text: By 1915, 1,000 automobiles per year were entering the park, resulting in conflicts with horses and horse-drawn transportation. Horse travel on roads was eventually prohibited.


title: Yellowstone National Park

text: The Civilian Conservation Corps (CCC), a New Deal relief agency for young men, played a major role between 1933 and 1942 in developing Yellowstone facilities. CCC projects included reforestation, campground development of many of the park's trails and campgrounds, trail construction, fire hazard reduction, and fire-fighting work. The CCC built the majority of the early visitor centers, campgrounds and the current system of park roads.


title: Yellowstone National Park

text: During World War II, tourist travel fell sharply, staffing was cut, and many facilities fell into disrepair. By the 1950s, visitation increased tremendously in Yellowstone and other national parks. To accommodate the increased visitation, park officials implemented Mission 66, an effort to modernize and expand park service facilities. Planned to be completed by 1966, in honor of the 50th anniversary of the founding of the National Park Service, Mission 66 construction diverged from the traditional log cabin style with design features of a modern style. During the late 1980s, most construction styles in Yellowstone reverted to the more traditional designs. After the enormous forest fires of 1988 damaged much of Grant Village, structures there were rebuilt in the traditional style. The visitor center at Canyon Village, which opened in 2006, incorporates a more traditional design as well.


title: Yellowstone National Park

text: The 1959 Hebgen Lake earthquake just west of Yellowstone at Hebgen Lake damaged roads and some structures in the park. In the northwest section of the park, new geysers were found, and many existing hot springs became turbid. It was the most powerful earthquake to hit the region in recorded history.


title: Yellowstone National Park

text: In 1963, after several years of public controversy regarding the forced reduction of the elk population in Yellowstone, United States Secretary of the Interior Stewart Udall appointed an advisory board to collect scientific data to inform future wildlife management of the national parks. In a paper known as the Leopold Report, the committee observed that culling programs at other national parks had been ineffective, and recommended management of Yellowstone's elk population.


title: Yellowstone National Park

text: The wildfires during the summer of 1988 were the largest in the history of the park. Approximately or 36% of the parkland was impacted by the fires, leading to a systematic re-evaluation of fire management policies. The fire season of 1988 was considered normal until a combination of drought and heat by mid-July contributed to an extreme fire danger. On "Black Saturday", August 20, 1988, strong winds expanded the fires rapidly, and more than burned.


title: Yellowstone National Park

text: The expansive cultural history of the park has been documented by the 1,000 archeological sites that have been discovered. The park has 1,106 historic structures and features, and of these Obsidian Cliff and five buildings have been designated National Historic Landmarks. Yellowstone was designated an International Biosphere Reserve on October 26, 1976, and a UN World Heritage Site on September 8, 1978. The park was placed on the List of World Heritage in Danger from 1995 to 2003 due to the effects of tourism, infection of wildlife, and issues with invasive species. In 2010, Yellowstone National Park was honored with its own quarter under the America the Beautiful Quarters Program.


title: Yellowstone National Park

text: Justin Ferrell explores three moral sensibilities that motivated activists in dealing with Yellowstone. First came the utilitarian vision of maximum exploitation of natural resources, characteristic of developers in the late 19th century. Second was the spiritual vision of nature inspired by the Romanticism and the transcendentalists in the mid-19th century. The twentieth century saw the biocentric moral vision that focuses on the health of the ecosystem as theorized by Aldo Leopold, which led to the expansion of federally protected areas and to the surrounding ecosystems.


title: Yellowstone National Park

text: The Heritage and Research Center is located at Gardiner, Montana, near the north entrance to the park. The center is home to the Yellowstone National Park's museum collection, archives, research library, historian, archeology lab, and herbarium. The Yellowstone National Park Archives maintain collections of historical records of Yellowstone and the National Park Service. The collection includes the administrative records of Yellowstone, as well as resource management records, records from major projects, and donated manuscripts and personal papers. The archives are affiliated with the National Archives and Records Administration.


title: Yellowstone National Park

text: Approximately 96 percent of the land area of Yellowstone National Park is located within the state of Wyoming. Another three percent is within Montana, with the remaining one percent in Idaho. The park is north to south, and west to east by air. Yellowstone is in area, larger than either of the states of Rhode Island or Delaware. Rivers and lakes cover five percent of the land area, with the largest water body being Yellowstone Lake at . Yellowstone Lake is up to deep and has of shoreline. At an elevation of above sea level, Yellowstone Lake is the largest high elevation lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland.


title: Yellowstone National Park

text: The Continental Divide of North America runs diagonally through the southwestern part of the park. The divide is a topographic feature that separates Pacific Ocean and Atlantic Ocean water drainages. About one third of the park lies on the west side of the divide. The origins of the Yellowstone and Snake Rivers are near each other but on opposite sides of the divide. As a result, the waters of the Snake River flow to the Pacific Ocean, while those of the Yellowstone find their way to the Gulf of Mexico.


title: Yellowstone National Park

text: The park sits on the Yellowstone Plateau, at an average elevation of above sea level. The plateau is bounded on nearly all sides by mountain ranges of the Middle Rocky Mountains, which range from in elevation. The highest point in the park is atop Eagle Peak () and the lowest is along Reese Creek (). Nearby mountain ranges include the Gallatin Range to the northwest, the Beartooth Mountains in the north, the Absaroka Range to the east, the Teton Range to the south, and the Madison Range to the west. The most prominent summit on the Yellowstone Plateau is Mount Washburn at .


title: Yellowstone National Park

text: Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials. This ash and other volcanic debris are believed to have come from the park area itself as the central part of Yellowstone is the massive caldera of a supervolcano. The park contains 290 waterfalls of at least , the highest being the Lower Falls of the Yellowstone River at .


title: Yellowstone National Park

text: Three deep canyons are located in the park, cut through the volcanic tuff of the Yellowstone Plateau by rivers over the last 640,000 years. The Lewis River flows through Lewis Canyon in the south, and the Yellowstone River has carved two colorful canyons, the Grand Canyon of the Yellowstone and the Black Canyon of the Yellowstone in its journey north.


title: Yellowstone National Park

text: Yellowstone is at the northeastern end of the Snake River Plain, a great U-shaped arc through the mountains that extends from Boise, Idaho some to the west.


title: Yellowstone National Park

text: The volcanism of Yellowstone is believed to be linked to the somewhat older volcanism of Snake River plain. Yellowstone is thus the active part of a hotspot that has moved northeast over time. The origin of this hotspot volcanism is disputed. One theory holds that a mantle plume has caused the Yellowstone hotspot to migrate northeast, while another theory explains migrating hotspot volcanism as the result of the fragmentation and dynamics of the subducted Farallon Plate in Earth's interior.


title: Yellowstone National Park

text: The Yellowstone Caldera is the largest volcanic system in North America, and worldwide it is only rivaled by the Lake Toba Caldera on Sumatra. It has been termed a "supervolcano" because the caldera was formed by exceptionally large explosive eruptions. The magma chamber that lies under Yellowstone is estimated to be a single connected chamber, about long, wide, and 3 to 7 miles (5 to 12 km) deep. The current caldera was created by a cataclysmic eruption that occurred 640,000 years ago, which released more than 240 cubic miles (1,000 km³) of ash, rock and pyroclastic materials. This eruption was more than 1,000 times larger than the 1980 eruption of Mount St. Helens. It produced a caldera nearly 5/8 of a mile (1 km) deep and in area and deposited the Lava Creek Tuff, a welded tuff geologic formation. The most violent known eruption, which occurred 2.1 million years ago, ejected 588 cubic miles (2,450 km³) of volcanic material and created the rock formation known as the Huckleberry Ridge Tuff and created the Island Park Caldera. A smaller eruption ejected 67 cubic miles (280 km³) of material 1.3 million years ago, forming the Henry's Fork Caldera and depositing the Mesa Falls Tuff.


title: Yellowstone National Park

text: Each of the three climactic eruptions released vast amounts of ash that blanketed much of central North America, falling many hundreds of miles away. The amount of ash and gases released into the atmosphere probably caused significant impacts to world weather patterns and led to the extinction of some species, primarily in North America.


title: Yellowstone National Park

text: A subsequent caldera-forming eruption occurred about 160,000 years ago. It formed the relatively small caldera that contains the West Thumb of Yellowstone Lake. Since the last supereruption, a series of smaller eruptive cycles between 640,000 and 70,000 years ago, has nearly filled in the Yellowstone Caldera with 80 different eruptions of rhyolitic lavas such as those that can be seen at Obsidian Cliffs and basaltic lavas which can be viewed at Sheepeater Cliff. Lava strata are most easily seen at the Grand Canyon of the Yellowstone, where the Yellowstone River continues to carve into the ancient lava flows. The canyon is a classic V-shaped valley, indicative of river-type erosion rather than erosion caused by glaciation.


title: Yellowstone National Park

text: Each eruption is part of an eruptive cycle that climaxes with the partial collapse of the roof of the volcano's partially emptied magma chamber. This creates a collapsed depression, called a caldera, and releases vast amounts of volcanic material, usually through fissures that ring the caldera. The time between the last three cataclysmic eruptions in the Yellowstone area has ranged from 600,000 to 800,000 years, but the small number of such climactic eruptions cannot be used to make an accurate prediction for future volcanic events.


title: Yellowstone National Park

text: The most famous geyser in the park, and perhaps the world, is Old Faithful geyser, located in Upper Geyser Basin. Castle Geyser, Lion Geyser, Beehive Geyser, Grand Geyser (the world's tallest predictable geyser), Giant Geyser (the world's most voluminous geyser), Riverside Geyser and numerous other geysers are in the same basin. The park contains the tallest active geyser in the world—Steamboat Geyser in the Norris Geyser Basin. A study that was completed in 2011 found that at least 1283 geysers have erupted in Yellowstone. Of these, an average of 465 are active in a given year. Yellowstone contains at least 10,000 thermal features altogether, including geysers, hot springs, mudpots, and fumaroles. Over half of the world's geysers and hydrothermal features are concentrated in Yellowstone.


title: Yellowstone National Park

text: In May 2001, the U.S. Geological Survey, Yellowstone National Park, and the University of Utah created the Yellowstone Volcano Observatory (YVO), a partnership for long-term monitoring of the geological processes of the Yellowstone Plateau volcanic field, for disseminating information concerning the potential hazards of this geologically active region.


title: Yellowstone National Park

text: In 2003, changes at the Norris Geyser Basin resulted in the temporary closure of some trails in the basin. New fumaroles were observed, and several geysers showed enhanced activity and increasing water temperatures. Several geysers became so hot that they were transformed into purely steaming features; the water had become superheated and they could no longer erupt normally. This coincided with the release of reports of a multiple year United States Geological Survey research project which mapped the bottom of Yellowstone Lake and identified a structural dome that had uplifted at some time in the past. Research indicated that these uplifts posed no immediate threat of a volcanic eruption, since they may have developed long ago, and there had been no temperature increase found near the uplifts. On March 10, 2004, a biologist discovered 5 dead bison which apparently had inhaled toxic geothermal gases trapped in the Norris Geyser Basin by a seasonal atmospheric inversion. This was closely followed by an upsurge of earthquake activity in April 2004. In 2006, it was reported that the Mallard Lake Dome and the Sour Creek Dome—areas that have long been known to show significant changes in their ground movement—had risen at a rate of per year from mid–2004 through 2006. As of late 2007, the uplift has continued at a reduced rate. These events inspired a great deal of media attention and speculation about the geologic future of the region. Experts responded to the conjecture by informing the public that there was no increased risk of a volcanic eruption in the near future. However, these changes demonstrate the dynamic nature of the Yellowstone hydrothermal system.


title: Yellowstone National Park

text: Yellowstone experiences thousands of small earthquakes every year, virtually all of which are undetectable to people. There have been six earthquakes with at least magnitude 6 or greater in historical times, including the 7.2‑magnitude Hebgen Lake earthquake which occurred just outside the northwest boundary of the park in 1959. This quake triggered a huge landslide, which caused a partial dam collapse on Hebgen Lake; immediately downstream, the sediment from the landslide dammed the river and created a new lake, known as Earthquake Lake. Twenty-eight people were killed, and property damage was extensive in the immediate region. The earthquake caused some geysers in the northwestern section of the park to erupt, large cracks in the ground formed and emitted steam, and some hot springs that normally have clear water turned muddy. A 6.1‑magnitude earthquake struck inside the park on June 30, 1975, but damage was minimal.


title: Yellowstone National Park

text: For three months in 1985, 3,000 minor earthquakes were detected in the northwestern section of the park, during what has been referred to as an earthquake swarm, and has been attributed to minor subsidence of the Yellowstone caldera. Beginning on April 30, 2007, 16 small earthquakes with magnitudes up to 2.7 occurred in the Yellowstone Caldera for several days. These swarms of earthquakes are common, and there have been 70 such swarms between 1983 and 2008. In December 2008, over 250 earthquakes were measured over a four-day span under Yellowstone Lake, the largest measuring a magnitude of 3.9. In January 2010, more than 250 earthquakes were detected over a two-day period. Seismic activity in Yellowstone National Park continues and is reported hourly by the Earthquake Hazards Program of the U.S. Geological Survey.


title: Yellowstone National Park

text: On March 30, 2014, a magnitude 4.8 earthquake struck almost the very middle of Yellowstone near the Norris Basin at 6:34 am; reports indicated no damage. This was the largest earthquake to hit the park since February 22, 1980.


title: Yellowstone National Park

text: Yellowstone National Park is the centerpiece of the Greater Yellowstone Ecosystem, a region that includes Grand Teton National Park, adjacent National Forests and expansive wilderness areas in those forests. The ecosystem is the largest remaining continuous stretch of mostly undeveloped pristine land in the contiguous United States, considered the world's largest intact ecosystem in the northern temperate zone. With the successful wolf reintroduction program, which began in the 1990s, virtually all the original faunal species known to inhabit the region when white explorers first entered the area can be found there.


title: Yellowstone National Park

text: Over 1,700 species of trees and other vascular plants are native to the park. Another 170 species are considered to be exotic species and are non-native. Of the eight conifer tree species documented, Lodgepole Pine forests cover 80% of the total forested areas. Other conifers, such as Subalpine Fir, Engelmann Spruce, Rocky Mountain Douglas-fir and Whitebark Pine, are found in scattered groves throughout the park. As of 2007, the whitebark pine is threatened by a fungus known as white pine blister rust; however, this is mostly confined to forests well to the north and west. In Yellowstone, about seven percent of the whitebark pine species have been impacted with the fungus, compared to nearly complete infestations in northwestern Montana. Quaking Aspen and willows are the most common species of deciduous trees. The aspen forests have declined significantly since the early 20th century, but scientists at Oregon State University attribute recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk.


title: Yellowstone National Park

text: There are dozens of species of flowering plants that have been identified, most of which bloom between the months of May and September. The Yellowstone sand verbena is a rare flowering plant found only in Yellowstone. It is closely related to species usually found in much warmer climates, making the sand verbena an enigma. The estimated 8,000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake, well above the waterline.


title: Yellowstone National Park

text: In Yellowstone's hot waters, bacteria form mats of bizarre shapes consisting of trillions of individuals. These bacteria are some of the most primitive life forms on earth. Flies and other arthropods live on the mats, even in the middle of the bitterly cold winters. Initially, scientists thought that microbes there gained sustenance only from sulfur. In 2005 researchers from the University of Colorado at Boulder discovered that the sustenance for at least some of the diverse hyperthermophilic species is molecular hydrogen.


title: Yellowstone National Park

text: "Thermus aquaticus" is a bacterium found in the Yellowstone hot springs that produces an important enzyme (Taq polymerase) that is easily replicated in the lab and is useful in replicating DNA as part of the polymerase chain reaction (PCR) process. The retrieval of these bacteria can be achieved with no impact to the ecosystem. Other bacteria in the Yellowstone hot springs may also prove useful to scientists who are searching for cures for various diseases. In 2016, researchers from Uppsala University reported the discovery of a class of thermophiles, Hadesarchaea, in Yellowstone's Culex Basin. These organisms are capable of converting carbon monoxide and water to carbon dioxide and hydrogen.


title: Yellowstone National Park

text: Non-native plants sometimes threaten native species by using up nutrient resources. Though exotic species are most commonly found in areas with the greatest human visitation, such as near roads and at major tourist areas, they have also spread into the backcountry. Generally, most exotic species are controlled by pulling the plants out of the soil or by spraying, both of which are time-consuming and expensive.


title: Yellowstone National Park

text: Yellowstone is widely considered to be the finest megafauna wildlife habitat in the lower 48 states. There are almost 60 species of mammals in the park, including the Rocky Mountain wolf, coyote, the Canadian lynx, cougars, and black and grizzly bears. Other large mammals include the bison (often referred to as buffalo), elk, moose, mule deer, white-tailed deer, mountain goat, pronghorn, and bighorn sheep.


title: Yellowstone National Park

text: The Yellowstone Park bison herd is the largest public herd of American bison in the United States. Bison once numbered between 30 and 60 million individuals throughout North America, and Yellowstone remains one of their last strongholds. Their populations had increased from less than 50 in the park in 1902 to 4,000 by 2003. The Yellowstone Park bison herd reached a peak in 2005 with 4,900 animals. Despite a summer estimated population of 4,700 in 2007, the number dropped to 3,000 in 2008 after a harsh winter and controversial brucellosis management strategies which sent hundreds to slaughter.


title: Yellowstone National Park

text: The Yellowstone Park bison herd is believed to be one of only four free roaming and genetically pure herds on public lands in North America. The other three herds are the Henry Mountains bison herd of Utah, at Wind Cave National Park in South Dakota and in Elk Island National Park in Alberta.


title: Yellowstone National Park

text: The relatively large bison populations are a concern for ranchers, who fear that the species can transmit bovine diseases to their domesticated cousins. About half of Yellowstone's bison have been exposed to brucellosis, a bacterial disease that came to North America with European cattle that may cause cattle to miscarry. The disease has little effect on park bison, and no reported cases of transmission from wild bison to domestic livestock have been filed. However, the Animal and Plant Health Inspection Service (APHIS) has stated that bison are the "likely source" of the spread of the disease in cattle in Wyoming and North Dakota. Elk also carry the disease, and are believed to have transmitted the infection to horses and cattle.


title: Yellowstone National Park

text: To combat the perceived threat of brucellosis transmission to cattle, national park personnel regularly corral bison herds back into the park when they venture outside of the area's borders. During the winter of 1996–97, the bison herd was so large that 1,079 bison that had exited the park were either shot or sent to slaughter. Animal rights activists argue that this is a cruel practice, and that the possibility for disease transmission is not as great as some ranchers maintain. Ecologists point out that the bison are merely traveling to seasonal grazing areas that lie within the Greater Yellowstone Ecosystem that have been converted to cattle grazing, some of which are within National Forests and are leased to private ranchers. APHIS has stated that with vaccinations and other means, brucellosis can be eliminated from the bison and elk herds throughout Yellowstone.


title: Yellowstone National Park

text: Starting in 1914, in an effort to protect elk populations, the U.S. Congress appropriated funds to be used for the purposes of "destroying wolves, prairie dogs, and other animals injurious to agriculture and animal husbandry" on public lands. Park Service hunters carried out these orders, and by 1926 they had killed 136 wolves. Gradually, wolves were virtually eliminated from Yellowstone. Further exterminations continued until the National Park Service ended the practice in 1935. With the passing of the Endangered Species Act in 1973, the wolf was one of the first mammal species listed. After the wolves were extirpated from Yellowstone, the coyote then became the park's top canine predator. Since the coyote is not able to bring down large animals, this lack of an apex predator resulted in a marked increase in lame and sick megafauna.


title: Yellowstone National Park

text: By the 1990s, the Federal government had reversed its views on wolves. In a controversial decision by the U.S. Fish and Wildlife Service (which oversees threatened and endangered species), northwestern wolves imported from Canada were reintroduced into the park. Reintroduction efforts have been successful, with populations remaining relatively stable. A survey conducted in 2005 reported that there were 13 wolf packs, totaling 118 individuals in Yellowstone and 326 in the entire ecosystem. These park figures were lower than those reported in 2004, but may be attributable to wolf migration to other nearby areas as suggested by the substantial increase in the Montana population during that interval. Almost all the wolves documented were descended from the 66 wolves reintroduced in 1995–96. The recovery of populations throughout the states of Wyoming, Montana and Idaho has been so successful that on February 27, 2008, the U.S. Fish and Wildlife Service removed the Northern Rocky Mountain wolf population from the endangered species list.


title: Yellowstone National Park

text: Black bears are common in the park and were a park symbol due to visitor interaction with the bears starting in 1910. Feeding and close contact with bears has not been permitted since the 1960s to reduce their desire for human foods. Yellowstone is one of the few places in the United States where black bears can be seen coexisting with grizzly bears. Black bear observations occur most often in the park's northern ranges, and in the Bechler area which is in the park's southwestern corner.


title: Yellowstone National Park

text: , an estimated 700 grizzly bears were living in the Greater Yellowstone Ecosystem, with about 150 grizzlies living wholly or partially within Yellowstone National Park. The grizzly was initially listed as a threatened species in the contiguous United States on July 28, 1975, by the Fish and Wildlife Service. The grizzly bear was taken off the endangered species list in 2007. Opponents of delisting the grizzly expressed concerns that states might once again allow hunting and that better conservation measures were needed to ensure a sustainable population. A federal district judge overturned the delisting ruling in 2009, reinstating the grizzly; however, the grizzly was once again removed from the list in 2017. In September 2018, a US district judge ruled that the grizzly's protections must be restored in full, arguing the Fish and Wildlife Service was mistaken in removing the bear from the threatened status list. Regardless of the rulings, hunting is prohibited within Yellowstone National Park. Hunters who legally hunt animals outside park boundaries may transport the carcass through the park with a permit.


title: Yellowstone National Park

text: Population figures for elk are in excess of 30,000—the largest population of any large mammal species in Yellowstone. The northern herd has decreased enormously since the mid‑1990s; this has been attributed to wolf predation and causal effects such as elk using more forested regions to evade predation, consequently making it harder for researchers to accurately count them. The northern herd migrates west into southwestern Montana in the winter. The southern herd migrates southward, and the majority of these elk winter on the National Elk Refuge, immediately southeast of Grand Teton National Park. The southern herd migration is the largest mammalian migration remaining in the U.S. outside of Alaska.


title: Yellowstone National Park

text: In 2003 the tracks of one female lynx and her cub were spotted and followed for over . Fecal material and other evidence obtained were tested and confirmed to be those of a lynx. No visual confirmation was made, however. Lynx have not been seen in Yellowstone since 1998, though DNA taken from hair samples obtained in 2001 confirmed that lynx were at least transient to the park. Other less commonly seen mammals include the mountain lion and wolverine. The mountain lion has an estimated population of only 25 individuals parkwide. Accurate population figures for the wolverine are not known. These uncommon and rare mammals provide insight into the health of protected lands such as Yellowstone and help managers make determinations as to how best to preserve habitats.


title: Yellowstone National Park

text: Eighteen species of fish live in Yellowstone, including the core range of the Yellowstone cutthroat trout—a fish highly sought by anglers. The Yellowstone cutthroat trout has faced several threats since the 1980s, including the suspected illegal introduction into Yellowstone Lake of lake trout, an invasive species which consume the smaller cutthroat trout. Although lake trout were established in Shoshone and Lewis lakes (on the Snake River drainage) after U.S. Government stocking operations in 1890, it was never officially introduced into the Yellowstone River drainage. The cutthroat trout has also faced an ongoing drought, as well as the accidental introduction of a parasite—whirling disease—which causes a terminal nervous system disease in younger fish. Since 2001, all native sport fish species caught in Yellowstone waterways are subject to a catch and release regulations.


title: Yellowstone National Park

text: Yellowstone is also home to seven species of reptiles, including the painted turtle, rubber boa, and prairie rattlesnake, bullsnake, sagebrush lizard, valley garter snake and wandering garter snake and four species of amphibians, including the boreal chorus frog, tiger salamander, western toad and columbia spotted frog.


title: Yellowstone National Park

text: Three hundred eleven species of birds have been reported, almost half of which nest in Yellowstone. In 1999, twenty-six pairs of nesting bald eagle were documented. Extremely rare sightings of whooping cranes have been recorded, however only three examples of this species are known to live in the Rocky Mountains, out of 385 known worldwide. Other birds, considered to be species of special concern because of their rarity in Yellowstone, include the common loon, harlequin duck, osprey, peregrine falcon and the trumpeter swan.


title: Yellowstone National Park

text: As wildfire is a natural part of most ecosystems, plants that are indigenous to Yellowstone have adapted in a variety of ways. Douglas-fir have a thick bark which protects the inner section of the tree from most fires. Lodgepole Pines—the most common tree species in the park—generally have cones that are only opened by the heat of fire. Their seeds are held in place by a tough resin, and fire assists in melting the resin, allowing the seeds to disperse. Fire clears out dead and downed wood, providing fewer obstacles for lodgepole pines to flourish. Subalpine Fir, Engelmann Spruce, Whitebark Pine, and other species tend to grow in colder and moister areas, where fire is less likely to occur. Aspen trees sprout new growth from their roots, and even if a severe fire kills the tree above ground, the roots often survive unharmed because they are insulated from the heat by soil. The National Park Service estimates that in natural conditions, grasslands in Yellowstone burned an average of every 20 to 25 years, while forests in the park would experience fire about every 300 years.


title: Yellowstone National Park

text: About thirty-five natural forest fires are ignited each year by lightning, while another six to ten are started by people—in most cases by accident. Yellowstone National Park has three fire lookout towers, each staffed by trained fire fighters. The easiest one to reach is atop Mount Washburn, which has interpretive exhibits and an observation deck open to the public. The park also monitors fire from the air and relies on visitor reports of smoke and/or flames. Fire towers are staffed almost continuously from late June to mid-September—the primary fire season. Fires burn with the greatest intensity in the late afternoon and evening. Few fires burn more than , and the vast majority of fires reach only a little over an acre (0.5 ha) before they burn themselves out. Fire management focuses on monitoring dead and down wood quantities, soil and tree moisture, and the weather, to determine those areas most vulnerable to fire should one ignite. Current policy is to suppress all human caused fires and to evaluate natural fires, examining the benefit or detriment they may pose on the ecosystem. If a fire is considered to be an immediate threat to people and structures, or will burn out of control, then fire suppression is performed.


title: Yellowstone National Park

text: In an effort to minimize the chances of out of control fires and threats to people and structures, park employees do more than just monitor the potential for fire. Controlled burns are prescribed fires which are deliberately started to remove dead timber under conditions which allow fire fighters an opportunity to carefully control where and how much wood is consumed. Natural fires are sometimes considered prescribed fires if they are left to burn. In Yellowstone, unlike some other parks, there have been very few fires deliberately started by employees as prescribed burns. However, over the last 30 years, over 300 natural fires have been allowed to burn naturally. In addition, fire fighters remove dead and down wood and other hazards from areas where they will be a potential fire threat to lives and property, reducing the chances of fire danger in these areas. Fire monitors also regulate fire through educational services to the public and have been known to temporarily ban campfires from campgrounds during periods of high fire danger. The common notion in early United States land management policies was that all forest fires were bad. Fire was seen as a purely destructive force and there was little understanding that it was an integral part of the ecosystem. Consequently, until the 1970s, when a better understanding of wildfire was developed, all fires were suppressed. This led to an increase in dead and dying forests, which would later provide the fuel load for fires that would be much harder, and in some cases, impossible to control. Fire Management Plans were implemented, detailing that natural fires should be allowed to burn if they posed no immediate threat to lives and property.


title: Yellowstone National Park

text: The spring season of 1988 was wet, but by summer, drought began moving in throughout the northern Rockies, creating the driest year on record to that point. Grasses and plants which grew well in the early summer from the abundant spring moisture produced plenty of grass, which soon turned to dry tinder. The National Park Service began firefighting efforts to keep the fires under control, but the extreme drought made suppression difficult. Between July 15 and 21, 1988, fires quickly spread from throughout the entire Yellowstone region, which included areas outside the park, to on the park land alone. By the end of the month, the fires were out of control. Large fires burned together, and on August 20, 1988, the single worst day of the fires, more than were consumed. Seven large fires were responsible for 95% of the that were burned over the next couple of months. The cost of 25,000 firefighters and U.S. military forces participating in the suppression efforts was 120 million dollars. By the time winter brought snow that helped extinguish the last flames, the fires had destroyed 67 structures and caused several million dollars in damage. Though no civilians died, two personnel associated with the firefighting efforts were killed.


title: Yellowstone National Park

text: Contrary to media reports and speculation at the time, the fires killed very few park animals—surveys indicated that only about 345 elk (of an estimated 40,000–50,000), 36 deer, 12 moose, 6 black bears, and 9 bison had perished. Changes in fire management policies were implemented by land management agencies throughout the United States, based on knowledge gained from the 1988 fires and the evaluation of scientists and experts from various fields. By 1992, Yellowstone had adopted a new fire management plan which observed stricter guidelines for the management of natural fires.


title: Yellowstone National Park

text: Yellowstone climate is greatly influenced by altitude, with lower elevations generally found to be warmer year-round. The record high temperature was in 2002, while the coldest temperature recorded is in 1933. During the summer months of June to early September, daytime highs are normally in the range, while night time lows can go to below freezing (0 °C) especially at higher altitudes. Summer afternoons are frequently accompanied by thunderstorms. Spring and fall temperatures range between with nights in the teens to single digits (−5 to −20 °C). Winter in Yellowstone is accompanied by high temperatures usually between zero and 20 °F (−20 to −5 °C) and nighttime temperatures below 0  °F (−18 °C) for most of the winter.


title: Yellowstone National Park

text: Precipitation in Yellowstone is highly variable and ranges from annually near Mammoth Hot Springs, to in the southwestern sections of the park. The precipitation of Yellowstone is greatly influenced by the moisture channel formed by the Snake River Plain to the west that was, in turn, formed by Yellowstone itself. Snow is possible in any month of the year, but most common between November and April, with averages of annually around Yellowstone Lake, to twice that amount at higher elevations.


title: Yellowstone National Park

text: The climate at Yellowstone Lake is classified as subarctic (Dfc), according to Köppen-Geiger climate classification, while at the park headquarters the classification is humid continental (Dfb).


title: Yellowstone National Park

text: Tornadoes in Yellowstone are rare; however, on July 21, 1987, the most powerful tornado recorded in Wyoming touched down in the Teton Wilderness of Bridger-Teton National Forest and hit Yellowstone National Park. Called the Teton–Yellowstone tornado, it was classified as an F4, with wind speeds estimated at between . The tornado left a path of destruction wide, and long, and leveled of mature pine forest.


title: Yellowstone National Park

text: In June 2022, the Park closed entrances and evacuated visitors after experiencing record-level rainfall and flooding that caused multiple road and bridge failures, power outages, and mudslides. A combination of heavy rain and rapid snow melt resulted in the Yellowstone River rising to a new record height at , breaking a previous record of set in 1918. Flooding on the Lamar River reached , beating a 1996 record of . Damage from the flooding includes washed out roads and bridges, and damage to infrastructure systems including electricity, water and wastewater systems. It's unlikely that the park will be able to reopen the north entrance by Gardiner, MT, or the northeast entrance near Cooke City, MT, during the 2022 season. The park partially reopened Wednesday, June 22, after a 9-day closure. To limit the nearly one million visitors per month that visit in the summer, the park has restricted entry to cars based on license plates. Cars with license plates ending in even numbers can enter on even numbered dates, and plates ending in odd numbers can enter on odd numbered dates.


title: Yellowstone National Park

text: Yellowstone ranks among the most popular national parks in the United States. Since the mid-1960s, at least 2 million tourists have visited the park almost every year. Average annual visitation increased to 3.5 million during the ten-year period from 2007 to 2016, with a record of 4,257,177 recreational visitors in 2016. July is the busiest month for Yellowstone National Park. At peak summer levels, 3,700 employees work for Yellowstone National Park concessionaires. Concessionaires manage nine hotels and lodges, with a total of 2,238 hotel rooms and cabins available. They also oversee gas stations, stores and most of the campgrounds. Another 800 employees work either permanently or seasonally for the National Park Service.


title: Yellowstone National Park

text: Park service roads lead to major features; however, road reconstruction has produced temporary road closures. Yellowstone is in the midst of a long term road reconstruction effort, which is hampered by a short repair season. In the winter, all roads aside from the one which enters from Gardiner, Montana, and extends to Cooke City, Montana, are closed to wheeled vehicles. Park roads are closed to wheeled vehicles from early November to mid April, but some park roads remain closed until mid-May. The park has of paved roads which can be accessed from five different entrances. There is no public transportation available inside the park, but several tour companies can be contacted for guided (including self-guided) motorized transport. In the winter, concessionaires operate guided snowmobile and snow coach tours, though their numbers and access are based on quotas established by the National Park Service. Facilities in the Old Faithful, Canyon and Mammoth Hot Springs areas of the park are very busy during the summer months. Traffic jams created by road construction or by people observing wildlife can result in long delays.


title: Yellowstone National Park

text: The National Park Service maintains nine visitor centers and museums and is responsible for maintenance of historical structures and many of the other 2,000 buildings. These structures include National Historical Landmarks such as the Old Faithful Inn built from 1903 to 1904 and the entire Fort Yellowstone – Mammoth Hot Springs Historic District. An historical and educational tour is available at Fort Yellowstone which details the history of the National Park Service and the development of the park. Campfire programs, guided walks and other interpretive presentations normally available at numerous locations in the summer, and on a limited basis during other seasons were suspended in 2021 as a COVID-19 response.