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Why California's Wildfires Are So Bad This Year

Even before the dramatic Southern California wildfires began their harrowing path this week, California was already experiencing its deadliest and most destructive fire season ever.

By Mark Gomez and Julia Prodis Sulek

Even before the dramatic Southern California wildfires began their harrowing path this week, California was already experiencing its deadliest and most destructive fire season ever.

And it's only getting worse.

In Ventura and Los Angeles counties, four fires driven by the Santa Ana winds are raging just two weeks before the start of winter, no less. By Wednesday, at least 150 homes had burned, including at least four in the star-studded enclave of Bel-Air. The flames reportedly damaged structures on media mogul Rupert Murdoch's estate and threatened the homes of other celebrities, including Tesla's Elon Musk. The Skirball fire closed Interstate 405 for a time on Wednesday, shuttered the landmark Getty Museum, and shut down classes at UCLA and the production of several TV series, including HBO's Westworld.

There's no sign of letting up. Thursday "is going to be the worst day with the winds," Cal Fire spokeswoman Lynne Tolmachoff said Wednesday. "We're expecting gusts up to or possibly worse than the North Bay fires. We are expecting gusts up to 80 mph."

Scenes of California burning are filling the airwaves just two months after the Wine Country fires made international headlines. Also on Wednesday, state officials announced the stunning cost of insurance claims in the October fires in Northern California had topped $9 billion. Those firestorms killed 44 people from Mendocino to Santa Rosa, burned 8,900 structures and destroyed scores of vehicles and other personal property.

While the North Bay fires alone turned 2017 into the deadliest wildfire season in state history, the Golden State is also closing in on a near-record year for acres burned. In 2008, nearly 1.6 million acres burned across the state; this year, before this week's fires, nearly 1.2 million acres had burned.

For Californians who welcomed one of the wettest, drought-busting winters early in 2017, the fury of the fires is startling. What's even more surreal, however, is the timing of the LA fires:

smack in the middle of the Christmas season, with trees in living rooms and colored lights under the eaves.

Southern California fires in December "aren't unprecedented," said Jan Null, meteorologist at Golden Gate Weather Services, but "generally, they have their biggest fires more in October and into November."

Of the 20 most destructive fires in California history, 11 of them occurred in October, including three from this year's Wine Country fires. Two were sparked in November, according to Cal Fire. None burned in December, although it's still too soon to know whether the Southern California fires have the destructive force to make the top 20 list.

"There's definitely potential," Cal Fire's Tolmachoff said.

Late season fires are "becoming more and more of the normal," she said. "Our fire seasons have become longer over the past couple of decades, increased by upwards of 70 days a year."

Still, December is unusual for such a huge, destructive fire. And there are two key factors at work: weather patterns and climate change.

Shortly after Northern California's deadly October wildfires, the region was doused with rains, all but ending the fire season here. But the storm track avoided the southern half of the state, which has received almost no precipitation in several months. Los Angeles has received less than two-tenths of an inch of rain since May 1.

"I was driving around Mendocino and Butte counties and there's green foliage coming back," Null said. "They haven't had that yet in Southern California to any extent."

The entire state is not likely to receive rain any time soon. A strong ridge of high pressure parked over much of the West Coast is blocking storms and sending them north to the U.S.-Canada border, according to the National Weather Service. Federal scientists are predicting all of California will remain dry at least through Dec. 20.

Climate change is also having effects that can only be factored over time.

"We get high risk, wind-driven fire seasons many years, but climate change is increasing the probability of extending it further into the fall or winter," said UC Merced Professor LeRoy Westerling, a climate and fire scientist.

Because of California's Mediterranean climate, where a handful of storms can make up the entire rainy season, missing two or three deluges can mean the difference between a wet and dry year.

"The timing becomes a lot more variable, too," Westerling said. "If you have three storms and not five, you might not get any in the fall."

And that leads to the kinds of devastating fire conditions this week in Los Angeles.

During California's five-year drought, "the winds that propel fires -- both the Santa Anas in Southern California and the Diablos in the north -- were not as great," Tolmachoff said. "We did get wind events, but they didn't last as long. These days we're talking about a five-day event with these Santa Anas. It's a big potential for fires to start and spread."

After the drought, this past winter's record-setting rains also spurred tremendous brush growth, which died off in the summer, making for extensive, ready fire fuel. Add the gusty winds ripping through new home developments, and the conditions are ripe for devastation.

That's what Ventura and Los Angeles counties have been experiencing this week, as the fires have forced thousands from their homes and led to a state of emergency declaration from Gov. Jerry Brown that will pave the way for more disaster relief. As of Wednesday afternoon, officials were bracing for more damage but relieved that no one had been killed.

"These are the days that break your heart," Los Angeles Mayor Eric Garcetti said, "but these are the days that keep us together."

Bay Area News Group wire services contributed to this report.

(c)2017 the San Jose Mercury News (San Jose, Calif.)

Caroline Cournoyer is GOVERNING's senior web editor.