Southern California fires are destructive and unprecedented — and a sign of things to come

Southern California this week looked like scenes from a disaster movie.

Flames from the Thomas Fire, spread by powerful Santa Ana winds, surrounded the mountain town of Ojai, a tourist mecca with a population of 7,500. The local hospital was forced to evacuate nearly 50 people in the middle of the night. They joined more than 200,000 residents across the Southland who have been told to leave their homes.

Drivers going through the Sepulveda Pass on the 405 freeway, in the heart of Los Angeles, watched in disbelief as the hills just off the side of the road burned bright red.

Gabriela Gutierrez lives with her husband and two young children at a mobile home park in Santa Paula, northwest of Los Angeles — or at least she did, until this week. She didn't believe it at first when she got a call from her family's babysitter, telling her people were being evacuated. Later a security guard knocked on her family's door, encouraging them to pack essentials. They eventually fled, going to stay with Gutierrez's mother.

The next day, Gutierrez was told her home had burned down.

"I was not believing it, so I went over there and I took a picture. I sent it to my husband — you know, we don't have nothing. I told him, we don't have nothing," Gutierrez later told a reporter. "At least we have our lives. We have our kids alive."

On some streets in Ventura, a middle-class city of 100,000 people near the ocean, home after home was reduced to slabs and rubble. Residents of Camp Bartlett, a small community in the mountains northeast of Ventura, returned to the rustic town on Thursday to discover five of the 12 cabins had burned down.

"We only left with our dogs and the clothes on our backs. And we came back, and it was all gone. Nothing was salvageable," said Christy Woodhams, who grew up in the town.

As the total area burned in Los Angeles and Ventura counties grew to more than 100,000 acres — 150 square miles — new fires broke out in Riverside and San Diego counties, stoked by Santa Ana winds that wouldn't let up. In San Diego County, where wind speeds were measured as high as 88 miles per hour, the Lilac Fire tore through the San Luis Rey Downs training facilities for race horses, killing an estimated 25 horses.

Only one person was reported to have been killed as a result of the fires so far, a 70-year-old Santa Paula woman who was found dead at the site of a car crash on an evacuation route . By contrast, the fires that tore through Northern California's Wine Country in October killed 42 people. Those were the deadliest blazes in state history.

But the damage in Southern California is still significant.

By Friday evening, half a dozen fires had destroyed more than 500 buildings. Regional air-quality officials issued several smoke advisories, warning people with respiratory illnesses or heart disease — and also pregnant women, children and the elderly — to stay indoors. Hundreds of schools shut down. The Russian cosmonaut Sergey Ryazansky tweeted photos of the conflagrations from the International Space Station, showing thick clouds of brown-white smoke blanketing Southern California, from the mountains to the ocean.

Crystal Kolden, a fire ecologist at the University of Idaho, said there was no precedent in modern history for this much fire in Southern California this late in the year. Kolden searched state fire records dating back to the 1800s and found just one fire, nearly 60 years ago, that had burned more than 50,000 acres in Southern California in December.

The ongoing Thomas Fire alone, by contrast, has already burned 132,000 acres.

"I think this sort of clustering of fires in December is definitely not something that we've seen," said Daniel Swain, a climate scientist at the University of California, Los Angeles.

Plenty of factors contribute to wildfire risk, from short-term variations in the weather, to development encroaching on forested areas, to federal budgets that prioritize fighting fires over preventing them. But scientists see the distinct fingerprints of human-caused climate change in the blazes destroying vast swaths of Southern California this week — and they say SoCal residents should prepare for more fire seasons like this one.

GET CAUGHT UP: Southern California fires: What we know

Several climate-driven trends came together to create prime fire conditions in Southern California this week, climate scientists say. For one, the state just experienced its hottest summer on record — by a lot . And so far, autumn and early winter have been the warmest such period in the recorded history of coastal Southern California, Swain said.

On top of that, "we're going more than six months without really any rain," Swain said.

Higher temperatures cause soils and vegetation to lose moisture earlier in the spring and stay dry later in the fall. Snowpack melts earlier, too, depriving ecosystems of a valuable source of moisture as summer temperatures dry out the landscape.

READ MORE: Record temperatures are making wildfire season worse

Climate change is also contributing to longer and more severe droughts in California, punctuated by wet years with bigger and more intense storms. Both of those trends have played a role in the recent fires, climate experts say. The Golden State recently emerged from a record-setting five-year drought, followed by one of its wettest winters on record — followed, in turn, by this year's record-hot summer, and an autumn with hardly any rain. All the vegetation that grew last winter is dried out and ready to burn.

"We've seen really wet falls and winters lately too, and then we've seen really dry ones. And that's the hallmark pattern you expect to see with climate change," said LeRoy Westerling, a fire ecologist at the University of California, Merced. "We had a much longer season of high-fire risk (this year) because we haven't gotten the rain."

There's even some research suggesting that climate change could make the Santa Ana winds more dangerous. Norman Miller, a climate scientist at the University of California, Berkeley, has run computer simulations showing climate change is likely to make the Santa Anas — which have stoked this week's fires — hotter, drier and more powerful.

But while there's no scientific consensus on a link between climate change and the Santa Ana winds, experts say Southern Californians should expect more fire seasons like this one. A growing body of research shows that fire season has gotten considerably longer across the West in recent decades, and that climate change is largely to blame.

CLIMATE POINT: Subscribe to USA TODAY's climate and energy newsletter

Westerling, for instance, published a study last year looking at wildfire frequency on federally managed forests across 11 western states. The numbers are eye-popping: There were five and a half times as many large fires from 2003-12 as there were from 1973-82, and a nearly thirteen-fold increase in the area burned by those fires. Meanwhile, the average length of the actual western fire season — as defined by the length of time between discovery of the first large fire and control of the last large fire — grew from 138 days in 1973-82 to 222 days in 2003-12. That's an increase of 84 days.

Another recent study , by researchers at the University of Idaho and Columbia University, found that from 1979 to 2015, climate change was responsible for more than half of the increase in dryness in western forests. That study also concluded that from 1984 to 2015, more than 10 million additional acres of forest burned because of climate change — a near-doubling of the area that would have been expected to burn otherwise.

In California and across the country, the average number of acres burned in wildfires has steadily risen in recent decades. Southern Californians can expect to see those trends to continue as humans keep emitting greenhouse gases, temperatures keep rising and the swings between drought and flood get more intense, Swain said.

"Even if the winds themselves don't change, (those trends) will drive more severe and larger Santa Ana wind-driven fires," Swain said. "This year is very much a preview."

Several journalists contributed to this report, including Wendy Leung from the Ventura County Star and Barrett Newkirk and Richard Lui from The Desert Sun.