A rare windstorm, unlike any in the past decade, whipped brush fires into unprecedented catastrophes, creating perhaps the two most destructive fires in Los Angeles County’s history, but neither of the ongoing blazes would have likely reached the same scale of destruction if it wasn’t for Southern California’s shifting climate, according to experts.
To start, a low pressure system pushed the region’s typical Santa Ana northerly winds to a higher elevation than usual, causing the winds to jump the basin’s mountains and descend to speeds of 80 to 100 mph into more widespread areas, affecting communities such as Pasadena that are typically protected from the strongest of seasonal gusts, according to Mike Wofford, a meteorologist at the National Weather Service.
“That’s a very unusual event,” Wofford said. “The last time we saw something of this magnitude would have been 2011.”
That past storm, roughly 13 years ago, similarly battered Pasadena and Altadena — where the more than 10,000-acre Eaton fire is burning today — felling trees, flipping vehicles and damaging hundreds of buildings. But it didn’t lead to significant fires.
The difference is what Daniel Swain, a climate scientist with the UCLA Institute of the Environment and Sustainability, is calling “hydroclimate whiplash.”
Essentially, Southern California experienced back-to-back extremely wet years in 2023 and early 2024, with annual rainfall reaching as high 43 inches in the Pasadena area and 26 inches in Santa Monica, according to the Los Angeles Almanac.
That rainfall spurred the growth of a significant amount of chapparal and grass in the areas now burning. Then the pendulum swung back.
“Since September, Southern California has seen the driest start to the winter on record, period, as well as among the hottest starts to the winter on record,” Swain said in a live broadcast Wednesday, Jan. 8.
This season, Pasadena has registered just 0.06 inches of rain so far, compared to 5.58 inches in a normal year. The lack of rainfall and hot temperatures created an “atmospheric blow dryer,” turning all of the lush vegetation into tinder, according to Swain.
“That sequencing from very wet to very dry is something that specifically facilitates abundant growth of herbaceous vegetation, and then the curing or drying of that to critically dry levels with the hot and dry conditions that follow,” he said.
Swain attributed the stronger-than-usual winds to “bad luck,” but the “real catalyst” for the catastrophe — the atypical dryness in the winter months — has not been seen before in records dating back to the 1800s, he said. Even if the windstorm had been weaker, Los Angeles County would have likely still experienced fires, he said. Similar conditions led to the Camp Fire, which killed 85 and destroyed more than 18,000 structures in Paradise in Northern California in 2018, Swain noted.
“This very strong wind event would not have produced a fire catastrophe had we gotten, say, an inch of rain in the past couple of weeks in Southern California, and I’m quite confident in that,” Swain said.
Though he estimated the Eaton fire and the Palisades fire, which has burned nearly 16,000 acres in the Santa Monica Mountains, are likely to become the most destructive — and costly fires — in Los Angeles County’s history, Swain said preparations and warnings ahead of the windstorm likely lessened the damage and saved lives.
Both the Eaton and Palisades fires were estimated to have burned more than 1,000 structures as of Wednesday evening. Officials believe at least five people have died as a result of the disasters.
Still, the speed that the fires spread left the county’s first responders scrambling to catch up.
Anthony Marrone, L.A County’s fire chief, told reporters at a Wednesday press conference that the county had prepared, but still found itself quickly spread thin. The heavy winds temporarily grounded firefighting aircraft overnight Tuesday, further slowing efforts to control the blazes.
“The L.A. County Fire Department was prepared for one or two major brush fires, but not four, especially given these sustained winds and low humidities,” Marrone said. “This is not a normal red flag alert.”
Alex Hall, director of UCLA’s Sustainable LA Grand Challenge, in a news release ahead of Tuesday’s windstorm, predicted the event would “drive home the point that we must learn to live with wildfire.”
“Whether we like it or not, the nature of wildfire in Southern California is changing, and we must adapt accordingly,” Hall said. “That will involve some frank conversations about the trade-offs involved in improving our strategies to reduce ignitions, improve stewardship of our unique chaparral landscapes to reduce impacts and protect human life and property.”
The worst of the windstorm has passed now, but Los Angeles County is not out of the woods yet — and may not see much of a break until Saturday at the earliest.
The critical fire conditions, exasperated by the Santa Ana winds, are expected to slow a bit going into Thursday, but then winds will pick up again to 30 to 50 mph in some areas on Friday, according to Wofford. By early next week, Southern California could return to yet “another traditional Santa Ana,” he said.