The largest wildfire in California’s history continued to rage Tuesday, after steadily growing for nearly two weeks. Unprecedented in scope, the Northern California fire has already consumed roughly 980 square miles and forced tens of thousands of people from their homes.
A pair of fires called the Mendocino Complex had been growing for nearly two weeks before combining Monday night to become the largest in modern state history, as firefighters battled to keep the flames from taking over residential areas.
The expanding blaze comes as more than 14,000 firefighters are working nonstop to fight back 17 separate wildfires across the state.
The fires have forced the state to use every resource available, including bringing in assistance from as far away as New Zealand and Australia along with thousands of volunteer inmate firefighters.
The Mendocino Complex Fire, which is burning northwest of Sacramento, reached more than 290,600 acres as of Tuesday morning, according to Cal Fire, the state’s fire agency. It overtook last year’s 282,000-acre Thomas Fire on Monday to become the largest California fire in a century of record-keeping.
Benjamin Nicholls, a division chief of Cal Fire, said on Tuesday morning that crews were battling the blaze along its northern edges, where it extends into mostly forested areas. He said crews were working on hot spots to make sure the fire does not creep into residential areas in the south.
“The increase of acreage is into the forest,” he said in an interview. “The fire is holding on the south side.”
Many firefighters have worked for two weeks without a break, and the fires have shown no sign of abating.
The Ferguson Fire has completely shut down swaths of Yosemite National Park indefinitely, leaving the hugely popular destination looking like a ghost town in what should be peak tourist season. Much of the Sacramento Valley is filled with smoke, and tourists in Lake Tahoe have reported canceling their vacations because of the choking haze.
In Redding, the Carr Fire has killed seven people, destroyed more than 1,000 homes and burned so badly that some ravaged neighborhoods are unrecognizable. It is the 12th largest in California history, at about 164,000 acres. While that fire has slowed down and residents have begun to return home, new fires in other parts of the state sent people fleeing Monday night.
A fire in the Cleveland National Forest exploded, easily consuming 4,000 acres and forcing evacuations from two canyons in Orange County. The smoke from that fire could be seen from as far away as Santa Catalina Island. Another Northern California fire in the Stanislaus National Forest destroyed a century-old resort.
Lynne Tolmachoff, a spokeswoman for Cal Fire, said on Monday that the state was only in the middle of its fire season, with the worst fires often occurring later in the year as the land becomes increasingly dry and weather patterns create windy conditions.
“We’ve got a long road ahead,” she said.
What was once referred to as a fire season has boomed into a year-round wildfire operation in California. In the last 10 months, fires have killed more than 40 people and burned down thousands of homes. The devastation began with the wine country fires in October, and just two months later fires in Santa Barbara and Ventura Counties became the largest in recorded state history. The record lasted only eight months. Four of California’s five largest wildfires in history have happened since 2012.
The fires are fueled by extreme heat and parched vegetation from years of drought. And firefighters have repeatedly been vexed by the soaring temperatures and rugged terrain of the current fires.
Scientists say climate change is a central factor in creating the atmospheric ingredients that make wildfires like California’s more extreme. Warmer global temperatures, driven by the greenhouse gases emitted from man-made activity like burning coal and driving cars, has led to droughts as well as more intense heat waves that last longer. The result: increasingly intense fire seasons that start earlier and last longer.
“You combine drought and heat, you get record wildfires. It’s not rocket science,” said Michael Mann, director of the Earth System Science Center at Pennsylvania State University.
Michael Wehner, a senior staff scientist at the Department of Energy’s Lawrence Berkeley National Laboratory, said it is still not possible to quantify the role that climate change plays versus other factors from more housing developments to the way forests are managed. But, Mr. Wehner said, “It’s fair to say that there is a human influence, and it’s not small.”
The Mendocino Complex Fire is a combination of two fires that ignited a few miles apart, Ms. Tolmachoff said. In instances where multiple blazes are close enough together and affect the same area, she said, officials consider them one fire, called a complex.
Officials are investigating the cause of the fire, which started on July 27 and was 34 percent contained as of early Tuesday. It has so far destroyed 143 structures, including 75 residences.
Despite its size, no one has died in the Mendocino Complex Fire, Ms. Tolmachoff said.
Of the top 20 largest wildfires in California, about half have come in the last decade, according to Cal Fire.
“That says a lot about the way things are changing in California,” Ms. Tolmachoff said.