Worsening Climate Change Boosts Risk of Destructive CA Wildfires

One fire appears to have been caused by a spark from old power lines, the other allegedly started by an Uber driver with a fascination with flames.

In the end, the Eaton and Palisades fires destroyed more than 16,000 homes, businesses and other structures and left 31 people dead. They were the second and third most destructive wildfires in California history — eclipsed only by the Camp fire that leveled the town of Paradise in 2018, destroying more than 18,000 structures and killing at least 85 people.

All three of those fires — and many others to hit California in recent decades — have one key factor in common: Global warming, which many scientists say is contributing to make California's always dangerous fire season be even more fraught than ever.

As climate change has worsened, California is suffering from larger fires. And most of the state's most destructive, deadliest and largest fires have occurred in the last quarter-century.

One study, published in 2023, said that summer forest fires in California have burned five times the area between 1996 and 2021 compared with the prior 25-year period.

"Climate change is contributing to this increase we've seen in fire activity," said John Abatzoglou, professor of climatology at UC Merced, one of the study's co-authors.

Climate change adds hazard to the other human factors that often spark massive fires. Not only are alleged arson and aging electrical infrastructure factors in the Jan. 7 firestorms, but so are how firefighters and officials made decisions before and during the fires, as well as the role of development into fire-prone wildlands and inadequate escape routes.

Record heat dried out SoCal to a crisp

The prelude to Southern California's most destructive fires in recorded history was Earth's hottest summer, and California's hottest July, in the record books.

In fact, summers have been heating up to an unprecedented degree — both in California and globally.

California and the West broiled during the last July before the Eaton and Palisades fires. Palm Springs marked its hottest day in recorded history, at 124 degrees; so did Las Vegas (120 degrees); Redding (119); Barstow (118); and Palmdale (115). Lancaster also hit 115, tying its all-time temperature high.

Globally, 2024 was also a year for the record books — the full year was the planet's hottest on record, worse than any other year in the NOAA record books that date to 1850.

All of that heat has alarming implications for California's wildfire risk — namely, drawing out the moisture from vegetation, according to a blog post by UCLA scientists on climate and weather factors leading up to the recent wildfires.

The summer and fall of 2024 were some of the hottest since at least 1895 in coastal Southern California, the scientists wrote, and high heat in the summer of 2024 "appears partly responsible for the steep summertime decline in dead fuel moisture."

Feast-or-famine rains

Another expected impact of climate change are increases in the dramatic dry-to-wet and wet-to-dry weather whiplash California faces. A separate study published in the journal Nature Reviews in January found that more episodes of "hydroclimate whiplash" are anticipated worldwide due to human-caused global warming.

"Hydroclimate whiplash has already increased due to global warming, and further warming will bring about even larger increases," the study's lead author, climate scientist Daniel Swain, said in January. "The whiplash sequence in California has increased fire risk twofold: first, by greatly increasing the growth of flammable grass and brush in the months leading up to fire season, and then by drying it out to exceptionally high levels with the extreme dryness and warmth that followed."

The deluge-to-drought pattern worsened the conditions of the vegetation leading up to January's fires.

California swung from its driest three-year period on record, from 2020 to 2022, to back-to-back wet years. By mid-2024, according to the UCLA scientists' blog post, the region was one of the greenest it had ever been since 2000.

Then, swaths of Southern California fell into a record dry start for the water year that began Oct. 1, 2024, with virtually no rain in the months leading to the January 2025 conflagration.

Before the January fires, the last significant rain in downtown Los Angeles was one-tenth of an inch on May 5. Between Oct. 1, 2024, the start of the water year, through Jan. 15, only 0.16 inches of rain had fallen, just 3% of the 5.56 inches in rainfall downtown received by that point, on average.

It had been about six decades since downtown was this parched. The only recorded comparable period that was even drier was Oct. 1, 1903, through Jan. 15, 1904, when only a trace of rain accumulated downtown.

Areas that recorded their driest first 3½ months of the water year on record included Los Angeles International Airport, UCLA, Van Nuys, Woodland Hills, San Diego, Lancaster and Camarillo.

With a "profound lack of precipitation across all of Southern California," Neil Lareau, associate professor of atmospheric science at the University of Nevada, Reno, said, "not only are the already dry fuels dry, but the live fuel moistures were very low, so it just supports that very rapid fire growth."

Virtually unprecedented Santa Ana winds

Another key factor behind the fires' devastation were severe Santa Ana winds. There's no evidence to blame increased severity of Santa Ana winds on climate change.

But they made already dangerous conditions terrifying. The extreme Santa Ana winds rapidly spread fires whose ignition points were in a worst-case locations — just upwind of heavily populated areas.

"In this case, you had a trifecta," said Michael Rohde, a former battalion chief with the Orange County Fire Authority who is now an emergency management consultant.

The fires, he said earlier this year, were spread by "ultra-strong winds — which was double the strength of a normal Santa Ana — and they come off those mountains and become urban conflagrations, and they have a lot more burning characteristic similarity with the Dresden firebombing in World War II."

An urban conflagration, which jumps from house to house through explosions of millions of embers, "is more intense than a normal wildland-urban interface fire," Rohde said. "And so we have these tremendous losses."

The winds of Jan. 6 and 7 were not a typical Santa Ana event. It was extraordinary, producing gusts of up to 100 mph, "about as extreme, just from wind, that we're going to see," said National Weather Service meteorologist Ryan Kittell. "We haven't seen winds like that since the 2011 wind storm that we had that really ravaged the Pasadena area."

The gusts were the product of mountain wave wind conditions, meaning they were oriented in a way where they would rapidly drop down the slopes of the San Gabriel Mountains, causing strong, dangerous bursts. A more moderate Santa Ana wind event typically funnels gusts through canyons, but isn't powerful enough to climb mountains.

This latest windstorm brought gusts from the north to northeast; in a typical Santa Ana wind event, they come from the east to northeast, said weather service meteorologist Rose Schoenfeld.

In other words, they hit areas that don't typically bear the brunt of the Santa Ana's strength — like Altadena and Pacific Palisades.

This story originally appeared in Los Angeles Times.

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