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These Are the Winds That Turn Wildfires Deadly in L.A.Skip to CommentsWind around Los Angeles on Jan. 7
Source: National Oceanic and Atmospheric Administration
Wind data is as of Jan. 7 at 10 a.m. Pacific time
These Are the Winds That Turn Wildfires Deadly in L.A.
Fierce desert winds turned this month’s wildfires around Los Angeles into raging cauldrons of devastation. They also made the blazes fit a pattern.
Fires driven by Santa Ana winds, the infamous gusts that howl in over the mountains to the city’s north, account for about 90 percent of the area burned by fall and winter wildfires in Southern California since 1950, scientists estimated in a recent study.
Southern California fires are often wind-driven in the cool months
Wildfires that began between October and March, since 1903
Hughes
Eaton
Los Angeles
Palisades
Long
Beach
Pacific Ocean
20 miles
Hughes
Oxnard
Eaton
San
Bernardino
Los Angeles
Palisades
Pacific Ocean
Long
Beach
Anaheim
20 miles
Sources: Cal Fire and National Interagency Fire Center
Note: 2025 data is as of Jan. 23.
High winds, another study found, are the most important factor for explaining whether large fires destroy homes and other structures there — not dry weather, not dense vegetation and not the fire’s proximity to areas where human settlements and wild spaces commingle, which is the critical factor in the San Francisco Bay Area and the foothills of the northern Sierra Nevada.
Such findings raise a big question for Los Angeles as it rebuilds: How can the area better gird itself against a threat as consistent, and consistently menacing, as severe wind?
Topography shapes which places are windiest
Average number of days with high wind speeds between October and March, since 2011
The Santa Ana winds flow from the desert over mountains and through canyons into the L.A. basin.
Soledad
Pass
Santa
Clarita
Cajon
Pass
Newhall
Pass
San Gabriel
Mountains
Malibu and
Topanga Canyons
Pasadena
Los Angeles
Long
Beach
Pacific
Ocean
Anaheim
20 miles
The Santa Ana winds flow from the desert over mountains and through canyons into the L.A. basin.
Soledad
Pass
Santa
Clarita
Newhall
Pass
Cajon
Pass
San Gabriel
Mountains
Malibu and
Topanga Canyons
Oxnard
Pasadena
San
Bernardino
Santa
Monica
Los Angeles
Pacific Ocean
Long
Beach
Anaheim
20 miles
Source: National Oceanic and Atmospheric Administration
Wind — fickle, invisible, shape-shifting wind — might not seem like the easiest force of nature to try to anticipate. And indeed, much about the winds that walloped Los Angeles early this month, including their ferocity, their positioning and the long spell of drought that preceded them, was out of the ordinary, even for Southern California.
“This was a very unique confluence of circumstances that just does not come together much at all,” said Ariel Cohen, the meteorologist in charge at the National Weather Service’s Los Angeles office.
Still, scientists say we know enough about Santa Anas to prepare better in several ways. We know they blow through every year, mostly in the cooler months. We know they tend to travel along certain corridors, through canyons and along hillsides where the rugged terrain steers and squeezes the desert air in its headlong rush toward the sea.
Wind-whipped wildfires are a “tractable problem,” said Jon Keeley, a fire ecologist at the United States Geological Survey. To him, the key is for electricity companies to figure out more precisely where and when to shut off power. This could stop many blazes from starting in the first place, although, as Dr. Keeley acknowledged, “that’s easier said than done.” (The authorities say they’re still investigating what ignited this month’s largest fires.)
Development in Santa Ana-prone areas could also be better regulated, said Max Moritz, a wildfire specialist at the University of California, Santa Barbara. California requires individual buildings in vulnerable places to meet fire-resistance standards. But there are no such standards for how communities should be designed to keep crowded neighborhoods away from flammable brush or how they should be laid out to help residents evacuate safely. “That’s the next frontier,” Dr. Moritz said.
Scenes from Altadena, Calif., this month.
To understand how Santa Anas can be consistent yet unpredictable, familiar yet capable of surprise, Dr. Cohen, the meteorologist, said it helps to think of pancake batter.
The winds begin with cool, dense air that builds up above Nevada and Utah, in the arid region known as the Great Basin. The atmosphere tries to right itself by drawing this air toward the coast. And so, like a mass of gooey batter spilling out of a bowl, the air starts spreading over the surrounding mountains. It gets funneled through narrow passes and canyons. It tumbles down slopes. It gets reshaped around obstacles, and spins out eddies and whirls.
Weather forecasters can narrow down the possibilities for where all this air ends up around Los Angeles and San Diego, and how quickly it’s moving when it gets there, Dr. Cohen said. But they can’t predict with certainty where the winds will be strongest. Nor, of course, where power lines or arsonists might start fires.
“All it takes is a slight reorientation” in the air, “and you go from relatively calm to a disaster scene,” Dr. Cohen said. Small shifts of this kind were what brought catastrophe this month to places, including Altadena, Burbank and Glendale, that don’t normally get hit by wind-stoked fires, Dr. Cohen said.
Still, firefighters in Southern California know very well which places channel the winds most often, said Mike Rohde, a former battalion chief with the Orange County Fire Authority. They even know which areas typically see wildfire earlier or later in the season, depending on how the canyons are oriented. “Like water,” the winds tend “to run down the same path the same way,” Mr. Rohde said.
California building codes aren’t blind to this fact. The state wildfire agency, Cal Fire, designates “fire hazard severity zones” based on burn history, vegetation, terrain and climate, including wind patterns. Homes in these zones have to be built to higher standards. They have to maintain buffers against their surroundings, both to keep flames from spreading and to help firefighters work safely.
But Cal Fire uses the same criteria statewide for determining hazard zones. That could be causing it to overlook certain regional differences, like how many destructive fires in Southern California are driven by wind rather than dry vegetation, said Alexandra Syphard, a research ecologist at the Conservation Biology Institute, a nonprofit science organization.
When the Santa Anas are at full blast, hurling embers thousands of feet and setting the landscape ablaze all around, how bad a fire gets isn’t primarily a question of how thick the shrubs on the ground are, Dr. Syphard’s research suggests. “The fires are spreading through the air and not the vegetation,” she said.
In an emailed statement, Cal Fire said it used localized data to estimate fire behavior at a fine scale, thereby accounting for regional differences when setting hazard zones. Experts say managing the vegetation in Southern California remains an important strategy for reducing wildfire risks in the summer.
The bigger question about the region’s fire corridors, said Mr. Rohde, the former battalion chief, is whether it makes sense to rebuild there at all.
“We know that the fire is going to re-burn in these locations, and we know it’s going to do it every so many years,” Mr. Rohde said. “We can’t continue to put people in harm’s way.”
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