A monsoonal storm approaches White Sands National Park in New Mexico.
From North America to the Amazon, from Sri Lanka and Northern Australia, the monsoon rains are an eagerly awaited event in many parts of the world. Here are some stormy photos of this extraordinary weather phenomenon, and the stories of the landscapes within them.
The sand grains at White Sands National Park are made from translucent gypsum. Wind movement rubs sand grains against each other, scratching them so that they appear white. The North American monsoon is often called the Desert Monsoon, as a large part of the affected area is arid or semi-arid. However, with the seasonal rains come many wildflowers can only bloom thanks to the annual downpour.
Dark storm clouds contrast dramatically with these red cliffs of New Mexico.
The Southwestern Monsoon of North America normally hits around the beginning of July, bringing about half the region's annual rainfall with it. New Mexico and Arizona are hit by wild winds and thunderstorms, with lighting strikes being common. The monsoon here is widely variable, both in its timings and the amount of precipitation, and is believed to be greatly affected by the El Nino/El Nina climate patterns.
Lighting crashes from purple clouds above Tucson, Arizona.
During the monsoon here, air currents bring moisture from the Pacific Ocean and the Gulf of Mexico, drastically changing the normally dry conditions of the region. Incidentally, 'monsoon' is a seasonal term like 'summer' or 'winter' and should be used the same way. Therefore, it is correct to say 'the monsoon thunderstorms are coming' rather than 'the monsoon is coming.' Also a monsoon technically includes a dry as well as a wet period, although it's generally only the latter that people refer to as a monsoon.
Banks of dark grey clouds build up around Malaysia's most famous urban landmark, the Petronas Towers.
Malaysia experiences two monsoons of differing intensity: the Southwest Monsoon from late May to September and the heavier Northwest Monsoon from November to March. The capital city, Kuala Lumpur, does not suffer too greatly from waterlogging during the rainy season but along the eastern coast, flooding is an annual event.
No matter how heavy the rain, life in monsoonal cities such as Saigon in Vietnam must go on. Unlike Malaysia, Vietnam experiences only one monsoon each year but it's an intense one, with up to 1000 mm of rainfall in most areas and up to 2500 mm in the sea-facing hills. Some regions are even subject to typhoons coming down from the South China Sea. Despite the destruction they sometimes bring, agriculture, particularly rice farming, could not survive without the annual rains.
Zanzibar is another of the regions to have two rainy seasons, a longer one (called Masika) from March to May, followed by more sporadic rainfall between October and December (called Vuli). The East African monsoons are really only part of the South Asian monsoon system, and the amount and duration of the rainfall can vary wildly. The West African monsoon, which brings much-needed rain to the Sudan and Sahel regions, is an entirely different system to the one experienced in the east.
The people of monsoonal countries get used to doing things in a downpour, like this friendly soccer match in Brazil. After all, there's only so much time you can spend indoors listening to the rain! Fortunately, most countries with a rainy season are quite warm so there's little danger of illness or hypothermia. The South American monsoon may be smaller than that of other continents, but it's still an important part of agriculture and ecology.
Scientists puzzled for many years about the South American monsoon, which covers a large area including the Amazon river basin. Although they knew that monsoons are caused by the reversal of the wind direction from land to ocean, they were unclear how this happens in South America. In other monsoonal regions, the storm clouds are brought on by low air pressure over hot landmasses, but in the Amazon rainforest, no such heated landmass exists. Recent research has come to the conclusion that the forest itself brings on the first thunderstorms that trigger the wet season, through transevaporation from millions of leaves. Another reason the Amazon jungle is so important!
One of the happy side-effects of heavy monsoonal clouds – stunning sunsets! For the last 300 years, scientists have understood monsoons as the movement of air currents between warm landmasses and the cooler ocean. However, recently scientists have begun to explore other theories, including the possibility that monsoons are caused not by different temperatures but by the interaction of tropical air circulation and turbulent air currents in middle latitudes. Research into the exact conditions that bring about monsoons continue.
Having your yearly rainfall come in a deluge during a short period of time can have some negative consequences, such as flooding. Floods occur in many countries during the rainy season and cause much hardship, especially in poorer nations. The situation is particularly dire in cyclone-prone regions such as Vanni in Sri Lanka (above), which was hit by Cyclone Nisha in 2008. Between 60,000 and 70,000 people were displaced.
There are various causes of flooding during a monsoon. For coastal areas, the problem can be incoming tides onto already waterlogged areas, or seasonal cyclones and hurricanes blowing in from the sea. Inland rivers can fill up and break their boundaries, filling floodplains and inundating low-lying areas. Occasionally, the floods happen quickly (as in flash flooding) which is particularly dangerous for inhabitants of the area. Other times, it is simply the result of the relentless rainfall that saturates the ground until it simply can't absorb any more, leading to slowly rising water levels.
India's countryside (like these 'ghats' or hills not far from Mumbai) transforms itself with the monsoon rains. The subcontinent has the most intense of all the monsoons, with 80% of its rainfall arriving between the months of June and September. A delayed or diminished rainy season has huge repercussions for agriculture and the economy. The same is also true of too much rain, which can cause floods and kill crops. Still, the splashing of the first raindrops is greeted with celebration in India, both in rural areas and in the cities, which look to the monsoon for relief from the baking summer heat.
Monsoon season in India is also a popular time for people to visit national parks and hill stations, and many take to the roads despite bad driving conditions. Otherwise sluggish rivers and waterfalls fill up during the rains to the delight of tourists as well as farmers. Even in urban areas, dust and pollution is washed off leaves and vegetation springs up in every patch of dirt. Sadly, much of it does not last long past the end of the monsoon.
Although much less intense than further south on the subcontinent, Nepal experiences two monsoons a year, the stronger summer monsoon and the more sporadic rainfall of the winter monsoon. The summer monsoon begins in June and is vital for rice farmers to irrigate their paddy fields. Too much rain, however, can bring on landslides and flooding and makes transport of supplies difficult. The winter monsoon is responsible for snow in the higher mountains and is important for crops in the lower areas, which rely on the meltwater for irrigation.
Barron Falls in Northern Queensland, Australia, really come alive from the added percipitation during the monsoon.
Known as the Indo-Australian monsoon, the wet season in Australia arrives during the summer and brings two thirds of the region's rainfall. This monsoon is a continuation of the one on the Indian subcontinent, and a connection has been found between snowfall in the Himalayas and rainfall in northern Australia. Like those of Arizona and New Mexico in Northern America, many of the plants in Northern Australia's drier regions only bloom during the monsoon.
An eerie light precedes a monsoon storm in the Thai capital Bangkok.
As with India, Thailand is at its lush, green best during the monsoon. Although it's not exactly cool, the rains do bring some relief from the otherwise hot, sticky weather of the capital. Traditionally, Buddhist monks in Thailand go on a religious retreat during the monsoon, a time which is set aside for study and reflection. During these three months, they are not allowed to travel outside their monasteries and are supported by devout laymen and -women.
The city of Shanghai seems to sit in the clouds during the East Asian monsoon, known poetically as the Plum Rain.
This weather system comes through in late spring and encompasses eastern China, Japan, Taiwan and Southern Korea. Mudslides and floods are a constant danger in this region during rainy season. Apart from flooding, one of the less desirable results of monsoon weather is fungus and mold, which can spoil food, fabrics, leather and even grow on walls.
The Tibetan Plateau is crucial in the formation of monsoon weather patterns in Asia, South Asia and as far away as Australia and East Africa. Its elevated landmass heats up to form an area of low pressure that draws in moist winds from the Indian Ocean. The plateau itself gets little precipitation due to the massive rain shadow formed by the Himalayan mountains where the moisture falls as snow.
As we have seen, the monsoon is a crucial weather pattern that affects life on our planet in ways both big and small. None of the earth's flora and fauna could live without the important drinking water that comes to us from the heavens for free. Think of that next time you grudgingly have to get out your umbrella!