Media playback is unsupported on your device Media caption With wildfires occurring across the globe, here are some of the techniques used to stop them

Twin wildfires in California, known as the Mendocino Complex Fire, have grown to become the largest active wildfire in state history, officials said on Monday.

The fires have spread rapidly in recent days to burn 283,800 acres of land - an area almost the size of Los Angeles.

Firefighters are tackling 16 major blazes across the state amid hot weather, strong winds and low humidity.

At least seven people have been killed in the Carr fire in the state's north.

Meanwhile US President Donald Trump has reiterated social media comments that the fires' spread is being "made so much worse" by California's environmental laws.

Local officials and experts have criticised and dismissed his tweets.

Where are the fires burning?

More than 14,000 firefighters and hundreds of US army personnel are trying to contain the more than a dozen major fires burning throughout the state.

National Weather Service meteorologist Brian Hurley has warned conditions are not going to immediately improve - with temperatures as high as 43C (110F) being forecast for some areas.

Officials say the Mendocino Complex Fire, which is made up of two nearby fires being treated as the same incident, has surpassed last year's Thomas Fire to become the largest in state history.

Scott McLean, a deputy chief with the California Department of Forestry and Fire Protection (CalFire) described the wildfires as "extremely fast, extremely aggressive, extremely dangerous,"

"Look how big it got, just in a matter of days... Look how fast this Mendocino Complex went up in ranking. That doesn't happen. That just doesn't happen," he said on Monday.

It is only 30% contained so far, with authorities warning it could take another week to get the blaze under control.

Media playback is unsupported on your device Media caption Experts say this has been the worst start to the fire season in 10 years

Experts say 2018 has the worst start to the fire season in 10 years - partly due to the 2012-2017 drought that killed off large amounts of vegetation.

In December, Governor Jerry Brown said devastating wildfires fuelled by climate change had become "the new normal".

What is the row with Mr Trump?

The US president has criticised Governor Jerry Brown and California's environmental laws on social media in recent days.

He tweeted on Monday that the wildfires were being "magnified & made so much worse" because of a Californian policy to divert water into the Pacific Ocean.

Skip Twitter post by @realDonaldTrump Governor Jerry Brown must allow the Free Flow of the vast amounts of water coming from the North and foolishly being diverted into the Pacific Ocean. Can be used for fires, farming and everything else. Think of California with plenty of Water - Nice! Fast Federal govt. approvals. — Donald J. Trump (@realDonaldTrump) August 6, 2018 Report

Skip Twitter post 2 by @realDonaldTrump California wildfires are being magnified & made so much worse by the bad environmental laws which aren’t allowing massive amounts of readily available water to be properly utilized. It is being diverted into the Pacific Ocean. Must also tree clear to stop fire from spreading! — Donald J. Trump (@realDonaldTrump) August 6, 2018 Report

Deputy fire chief Mr Mclean dismissed Mr Trump's comments to US media, saying firefighters had "plenty of water" to tackle these wildfires.

"Our changing climate is leading to more severe and destructive fires that we are seeing this year and last," he told Time magazine.

Some believe Mr Trump's tweets refer to a row about water supplies, fish habitat protection and local farmers - but environmental experts say this has no relevance to the state's firefighting capability.</s>The River and Ranch wildfires in Northern California, known as the Mendocino Complex Fire, continue to rage out of control, now having burned more than 283,000 acres. The two blazes that began burning through Northern California late last month have grown at breathtaking speed to form a massive inferno that has now set a new mark for destruction, reports the Washington Post.

The twin wildfires have together more than doubled in size in the past four days and burned an area almost the size of Los Angeles. By Monday night, the Mendocino Complex Fire had earned an infamous distinction, becoming the largest wildfire ever recorded in California, according to Cal Fire.

It has now surpassed the Thomas Fire that burned nearly 282,000 acres of land in Ventura and Santa Barbara counties late last year and the Cedar Fire that killed 15 people in San Diego County 15 years ago.

Fueled by low humidity, triple-digit temperatures and winds blowing across wide swaths of tinder-dry vegetation, the Mendocino Complex Fire showed little sign of slowing Tuesday, spreading to three counties, surrounded a river and parts of neighboring reservoirs, and destroyed and damaged nearly 170 homes and other structures.

Typically, temperatures dip and humidity rises overnight, giving firefighters a window to slow the fires’ progress. But this has not happened.</s>A wildfire burning through Northern California became the state’s largest on record on Monday, scorching more than 283,000 acres, officials said.

The Mendocino Complex blaze — a conglomerate of two separate fires burning through rural Lake, Colusa and Mendocino counties — overtook last year’s Thomas Fire, which scorched more than 1,000 buildings and killed two people across 440 square miles in Ventura and Santa Barbara Counties.

The fire began on July 27 and was spurred on Monday by an ominous high-pressure system that brought hotter, drier and windier weather to the area, according to the California Department of Forestry and Fire Protection, or Cal Fire.

The fire has destroyed dozens of homes and other buildings, and more than 11,000 structures remained threatened, the department said.

Mandatory evacuations remained in effect across Mendocino, Lake and nearby Colusa counties, though some people were allowed to return home on Monday afternoon, Cal Fire said.

Nearly 4,000 fire personnel, including 441 fire fighters, were battling the wildfire.

It was unclear what caused the blaze, but the fire was one of several burning amid record-setting heat waves in the drought-stricken state. Tens of thousands of residents across California have been displaced by wildfires this season, Gov. Jerry Brown told reporters Saturday.

President Donald Trump declared a state of emergency in California on July 27, authorizing the Federal Emergency Management Agency to help firefighters working to respond to the disaster areas.</s>CLEARLAKE, Calif. — Reinforcements have been called in to fight 16 large wildfires in California, with the Army sending 200 soldiers to battle the blazes from the air. The fires are being fed by strong winds and high temperatures, and parts of the Mendocino Complex Fire are proving to be unstoppable.

Firefighters in Lake and Mendocino counties ignited more back burns overnight to remove tinder-dry brush fueling this massive wildfire. But fierce, hot winds continue to whip flames into a frenzy. A Cal Fire spokesperson predicts it could become the largest in state history by Tuesday.

More than 400 square miles have been scorched, making this California's second largest fire on record. Will Powers, a fire prevention specialist with Cal Fire, said the heat and dryness are fueling the blaze.

"We're going back into the high 90s. It's making for some extreme fire behavior," Powers said.

The growing inferno sparked new evacuations. It has already destroyed 75 homes and threatens 9,300 structures.

Farther north near Redding, the Carr Fire has claimed a seventh life. Utility worker Jairus Ayeta died in a vehicular accident while he was trying to restore power in dangerous terrain. The fire is entering its third week, with 163,000 acres burned and more than 1,000 homes lost.

As large swaths of California continue to burn, President Trump is jumping into the debate over how to best fight these wildfires. The president criticized Gov. Jerry Brown on Twitter, saying he "must allow the Free Flow of the vast amounts of water coming from the North and foolishly being diverted into the Pacific Ocean."

But Cal Fire officials said there has not been a situation where crews needed water and couldn't access it.

The Mendocino Complex fire is burning close to the shoreline of Clear Lake, the largest natural freshwater lake entirely within the state of California. Throughout this busy fire season, firefighters here in Northern California have not indicated that a lack of water is hampering their efforts to fight these fires or contributing to their growth.</s>LAKEPORT, Calif. – Twin Northern California blazes fueled by dry vegetation and hot, windy weather grew Monday to become the largest wildfire in state history, becoming the norm as climate change makes the fire season longer and more severe.

The two fires burning a few miles apart and known as the Mendocino Complex are being treated as one incident. It has scorched 283,800 acres (443.4 square miles or 1,148.4 square kilometers), fire officials said Monday.

The fires, north of San Francisco, have burned 75 homes and is only 30 percent contained.

The size of the fires surpasses a blaze last December in Southern California that burned 281,893 acres (440.5 square miles or 1,140.8 kilometers). It killed two people, including a firefighter, and destroyed more than 1,000 buildings before being fully contained on Jan. 12.

Flames leap above a vehicle on High Valley Rd. as the Ranch Fire, part of the Mendocino Complex Fire, burns near Clearlake Oaks, Calif., on August 5, 2018.

Hotter weather attributed to climate change is drying out vegetation, creating more intense fires that spread quickly from rural areas to city subdivisions, climate and fire experts say. But they also blame cities and towns that are expanding housing into previously undeveloped areas.

More than 14,000 firefighters are battling over a dozen major blazes throughout California, state Department of Forestry and Fire Protection spokesman Scott McLean said.

“I can remember a couple of years ago when we saw 10 to 12,000 firefighters in the states of California, Oregon and Washington and never the 14,000 we see now,” he said.

Crews did make progress over the weekend against one of the two blazes in the Mendocino Complex with help from water-dropping aircraft, Cal Fire operations chief Charlie Blankenheim said in a video on Facebook.

But the other one is growing after spreading into the Mendocino National Forest.

More: California firefighters battle an enemy they can't beat

Also: What Trump is getting wrong about California's wildfires and water

The complex of fire has been less destructive to property than some of the other wildfires in the state because it is mostly raging in remote areas. But officials say the twin fires threaten 11,300 buildings and some new evacuations were ordered over the weekend as the flames spread.

Farther north, crews gained ground against a deadly blaze that has destroyed more than 1,000 homes in and around Redding. It was nearly halfway contained, Cal Fire said.

The wildfire about 225 miles (360 kilometers) north of San Francisco started more than two weeks ago by sparks from the steel wheel of a towed-trailer’s flat tire. It killed two firefighters and four residents and displaced more than 38,000 people.

Officials began allowing some residents to return to their neighborhoods. But tens of thousands of others were still evacuated.

The fires in Northern California have created such a haze of smoke in the Central Valley that Sacramento County health officials advised residents to avoid outdoor activities for the entire week.

Another blaze that ignited last week has damaged a historic Northern California resort in the Stanislaus National Forest. The nearly century-old Dardanelle Resort has sustained massive structural damage, though the details were unclear, the Sacramento Bee newspaper reported.

The rustic lodge 180 miles (290 kilometers) east of San Francisco is nestled in the Sierra Nevada mountains and offers cabin and motel rentals along with RV sites, a store and restaurant.

The U.S. Forest Service reported that the fire crossed a highway Sunday evening, forcing crews to retreat from the fire’s edge.

The resort owners said in a Facebook post that “at this point it has been confirmed that there is ‘massive structural damage.’ We are heartbroken and struggling with this news.”</s>A wildfire burning through Northern California became the state’s largest on record on Monday, scorching more than 290,000 acres, officials said.

The Mendocino Complex blaze — a conglomerate of the River and Ranch fires burning through rural Lake, Colusa and Mendocino counties — overtook last year’s Thomas Fire, which scorched more than 1,000 buildings and killed two people across 440 square miles in Ventura and Santa Barbara Counties.

The fire began on July 27 and was spurred on Monday by an ominous high-pressure system that brought hotter, drier and windier weather to the area, according to the California Department of Forestry and Fire Protection, or Cal Fire.

The fire has destroyed dozens of homes and other buildings, and more than 11,000 structures remained threatened, the department said.

The Mendocino Complex blaze reached 443 square miles, almost twice the size of Tucson, Arizona — which is about 226.7 square miles.

As of Tuesday, the Mendocino Complex blaze was only 30 percent contained. Firefighters expect the fire will be fully contained by Aug. 15.

Mandatory evacuations remained in effect across Mendocino, Lake and nearby Colusa counties, though some people were allowed to return home on Monday afternoon, Cal Fire said.

The fires have created such a haze of smoke in the Central Valley that Sacramento County health officials advised residents to avoid outdoor activities for the entire week.

Nearly 4,000 fire personnel, including 441 firefighters, were battling the wildfire.

It was unclear what caused the blaze, but the fire was one of more than a dozen burning amid record-setting heat waves in the drought-stricken state, according to Cal Fire.

Tens of thousands of residents across California have been displaced by wildfires this season, Gov. Jerry Brown told reporters Saturday.

California's record-breaking heat last month, with temperatures in the triple digits for days, helped fuel the wildfires, and they have been rekindled in August as temperatures again approach triple digits across the state.

Temperatures in parts of Northern California were expected to exceed 100 degrees on Tuesday, according to Weather.com. Colusa, California, where part of the Mendocino Fire Complex is burning, was also expected to reach 103 degrees, and the forecast for the rest of the month shows temperatures in the mid- to high-90s.

President Donald Trump declared a state of emergency in California on July 27, authorizing the Federal Emergency Management Agency to help firefighters to respond to the disaster areas.

More than 14,000 firefighters are now battling over a dozen major blazes throughout California, Cal Fire spokesman Scott McLean said.

A new fire erupted Monday in Orange County, south of Los Angeles, and prompted the evacuation of two canyons and some campgrounds as it expanded into the Cleveland National Forest. By nightfall, the fire had burned 4,000 acres of chaparral-covered hillsides and destroyed one building.</s>The Mendocino Complex fire in Northern California has just grown to become the largest wildfire in state history, devouring more than 290,000 acres. Photo: Getty Images

SAN FRANCISCO—Firefighters warned Tuesday it could take a month to contain the largest wildfire in California’s history.

The blaze—the second time in eight months a wildfire has claimed a record size—is prompting questions about where people should live and build long-term in a state that has increasingly pushed new development into what are now fire-prone areas. It’s early in the wildfire season.</s>LAKEPORT, Calif. — Wildfires tearing through trees and brush, rampaging up hillsides and incinerating neighborhoods: The place-names change but the devastation is showing signs of becoming the new normal in California.

On Monday, twin fires being treated as one incident north of San Francisco became the largest wildfire in state history, destroying 443 square miles (1,148 square kilometers) — nearly the size of the city of Los Angeles.

The Mendocino Complex was still growing as it broke the record set last December. The Thomas Fire killed two people, burned 440 square miles, and destroyed more than 1,000 buildings in Southern California before being fully contained Jan. 12.

The Mendocino Complex, which is 30 percent contained, has been less destructive to property than some of the other wildfires in the state because it is mostly raging in remote areas. But officials say it threatens 11,300 buildings and some new evacuations were ordered over the weekend as the flames spread.

Hotter weather attributed to climate change is drying out vegetation, creating more intense fires that spread quickly from rural areas to city subdivisions, climate and fire experts say. But they also blame cities and towns that are expanding housing into previously undeveloped areas.

More than 14,000 firefighters are battling more than a dozen major blazes throughout California, state Department of Forestry and Fire Protection spokesman Scott McLean said.

"I can remember a couple of years ago when we saw 10 to 12,000 firefighters in the states of California, Oregon and Washington and never the 14,000 we see now," he said.

Crews made progress over the weekend against one of the two blazes in the Mendocino Complex with help from water-dropping aircraft, Cal Fire operations chief Charlie Blankenheim said in a video on Facebook.

But the other one is growing after spreading into the Mendocino National Forest.

Meanwhile, a new fire erupted south of Los Angeles in Orange County on Monday and quickly spread through the chaparral-covered ridges of the Cleveland National Forest. Campgrounds and homes in Holy Jim Canyon were ordered evacuated. The fire sent up an enormous pillar of smoke and ash.

Farther north, crews gained ground against a deadly blaze that has destroyed more than 1,000 homes in and around Redding. It was nearly halfway contained, Cal Fire said.

The wildfire about 225 miles (360 kilometers) north of San Francisco started more than two weeks ago by sparks from the steel wheel of a towed-trailer's flat tire. It killed two firefighters and four residents and displaced more than 38,000 people.

Officials began allowing some residents to return to their neighborhoods. But tens of thousands of others were still evacuated.

The fires in Northern California have created such a haze of smoke in the Central Valley that Sacramento County health officials advised residents to avoid outdoor activities for the entire week.

Another blaze that ignited last week in the Sierra Nevada has damaged a historic Northern California resort in the Stanislaus National Forest. The nearly century-old Dardanelle Resort has sustained massive structural damage, though the details were unclear, the Sacramento Bee newspaper reported.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.</s>It’s the second year in a row that California has recorded the state’s largest wildfire.

FILE - In this Tuesday, July 31, 2018, file photo, a firefighter runs while trying to save a home as a wildfire tears through Lakeport, Calif. The residence eventually burned. Authorities say a rapidly expanding Northern California wildfire burning over an area the size of Los Angeles has become the state’s largest blaze in recorded history. (AP Photo/Noah Berger, File)

Wildfires tearing through trees and brush, rampaging up hillsides and incinerating neighbourhoods: The place-names change but the devastation is showing signs of becoming the new normal in California.

On Monday, twin fires being treated as one incident north of San Francisco became the largest wildfire in state history, destroying 443 square miles (1,148 square kilometres) — nearly the size of the city of Los Angeles.

The Mendocino Complex was still growing as it broke the record set last December. The Thomas Fire killed two people, burned 440 square miles, and destroyed more than 1,000 buildings in Southern California before being fully contained Jan. 12.

The Mendocino Complex, which is 30 per cent contained, has been less destructive to property than some of the other wildfires in the state because it is mostly raging in remote areas. But officials say it threatens 11,300 buildings and some new evacuations were ordered over the weekend as the flames spread.

Hotter weather attributed to climate change is drying out vegetation, creating more intense fires that spread quickly from rural areas to city subdivisions, climate and fire experts say. But they also blame cities and towns that are expanding housing into previously undeveloped areas.

More than 14,000 firefighters are battling more than a dozen major blazes throughout California, state Department of Forestry and Fire Protection spokesman Scott McLean said.

“I can remember a couple of years ago when we saw 10 to 12,000 firefighters in the states of California, Oregon and Washington and never the 14,000 we see now,” he said.

Crews made progress over the weekend against one of the two blazes in the Mendocino Complex with help from water-dropping aircraft, Cal Fire operations chief Charlie Blankenheim said in a video on Facebook.

Related: Back to rubble, some ‘lost everything’ in California fire

But the other one is growing after spreading into the Mendocino National Forest.

Meanwhile, a new fire erupted south of Los Angeles in Orange County on Monday and quickly spread through the chaparral-covered ridges of the Cleveland National Forest. Campgrounds and homes in Holy Jim Canyon were ordered evacuated. The fire sent up an enormous pillar of smoke and ash.

Farther north, crews gained ground against a deadly blaze that has destroyed more than 1,000 homes in and around Redding. It was nearly halfway contained, Cal Fire said.

The wildfire about 225 miles (360 kilometres) north of San Francisco started more than two weeks ago by sparks from the steel wheel of a towed-trailer’s flat tire. It killed two firefighters and four residents and displaced more than 38,000 people.

Officials began allowing some residents to return to their neighbourhoods. But tens of thousands of others were still evacuated.

The fires in Northern California have created such a haze of smoke in the Central Valley that Sacramento County health officials advised residents to avoid outdoor activities for the entire week.

Another blaze that ignited last week in the Sierra Nevada has damaged a historic Northern California resort in the Stanislaus National Forest. The nearly century-old Dardanelle Resort has sustained massive structural damage, though the details were unclear, the Sacramento Bee newspaper reported.

Like us on Facebook and follow us on Twitter.</s>The raging Mendocino Complex fire has officially become the largest wildfire in California's history, authorities have confirmed. Firefighters continue to battle the blaze, which is currently only 30 percent contained. “We broke the record,” Department of Forestry and Fire Protection spokesman Scott McLean said. “That’s one of those records you don’t want to see.” The Ranch and River fires that make up the Mendocino Complex wildfire had grown to 283,800 acres by Monday evening, Cal Fire said in their latest update. Some 3,908 firefighters, 441 fire engines, and 15 aircraft continue to battle the flames.
The Mendocino Complex Fire grows into the largest active wildfire in California history.