Tiny burning embers flew miles, causing L.A. fire destruction on historic scale
Santa Ana winds are infamous for driving fast-moving fires in Southern California, pushing embers well beyond a blaze’s boundary and into neighborhoods and across major roadways.
But officials say the winds that fueled devastating fires in three parts of Los Angeles County were much more erratic and unpredictable than a typical dry offshore wind pattern — and struck areas unaccustomed to such events.
Five people have died, but officials say the death toll is likely to be higher. More than 2,000 structures have burned and at least 130,000 residents are under evacuation orders. Experts say L.A. is not out of danger yet and these fires have the potential to be the costliest wildfire disaster in American history.
The life-threatening windstorm that prompted several days of dire warnings exploded into a crisis even worse than firefighters predicted, with embers flying an estimated two to three miles ahead of the established fire and in every direction.
The extraordinary winds have created extreme fire behavior almost impossible to anticipate, confounding efforts to establish secure containment lines or utilize firefighting aircraft. They have also led to major structure losses, widespread evacuations and ongoing destruction.
“Normally, under a sustained Santa Ana condition, we have fires that are long and narrow,” said Anthony Marrone, Los Angeles County Fire Chief. “However, with these erratic winds and this PDS, or particularly dangerous situation, the winds were constantly changing.”
On top of typical long-range spotting during such an offshore wind event, ember casts were flying in several directions, sometimes switching course throughout the day, Marrone said. As much as the major wildfires were spreading seaward — as is typical during Santa Anas — the blazes were growing laterally, he said.
“This was just different,” Marrone said.
The Palisades fire, which sparked early Tuesday, has destroyed more than 1,000 structures in Pacific Palisades and has surged to more than 15,000 acres as of Wednesday afternoon. The Eaton fire sparked later in the day, but spread rapidly through Altadena and Pasadena, destroying at least 100 buildings as it exploded to over 10,000 acres. At least five people have died in the Eaton fire.
The Palisades fire has burned more than 17,000 acres and 1,000 structures, including many homes, while five people have died in the Eaton fire. At least 130,000 residents are under evacuation orders.
In Sylmar, the Hurst fire has grown to 700 acres.
More than 65,000 people are under evacuation orders because of the three fires, and thousands more have been warned they could be next. All three fires have no containment, per fire officials.
“This wildfire was the most chaotic winds I’ve experienced in 20 years,” Capt. Erik Scott, a Los Angeles Fire Department spokesperson, said of the Palisades blaze. He said the 2018 Woolsey fire — which burned almost 100,000 acres in southeast Ventura County and Malibu, destroying 1,500 structures and killing three people — was the only fire in Southern California that saw winds anywhere close to those this week.
“These were the chaotic winds that we were absolutely worried would create the explosive fire behavior that we do have,” Scott said. “It’s not just the flame fronts that take out houses. It’s the ember cast that can fly a mile or two in front and will land on a property or go in somebody’s attic and burn homes from the top down.”
Gusts hit dangerously high speeds in areas that rarely see such bursts.
Forecasters warned of a phenomenon that can cause short-lived but extremely destructive winds, particularly in the San Gabriel Valley and foothills. This “mountain wave wind” activity occurs when gusts rapidly drop down mountain slopes, then gain strength upon hitting a flat landscape, causing “brief bursts of very strong, dangerous winds,” said National Weather Service meteorologist Rich Thompson — which could reach 80 to 100 mph.
That proved spot on. Gusts over 80 mph were detected late Tuesday and into Wednesday morning, including one that hit 100 mph at 5 a.m. near Altadena, the weather service said. Those extreme gusts were likely caused by “mountain wave wind” activity, meteorologist Rose Schoenfeld said Wednesday morning.
Neil Lareau, a professor of atmospheric science at the University of Nevada Reno, said on social media that the winds around the Eaton fire were “strongly forced” — so powerful they could crest and descend the San Gabriel Mountains. By contrast, the flow of less extreme Santa Ana winds would be partially blocked and channeled through canyons — through so-called Santa Ana wind corridors.
It didn’t help that the region was primed for wildfire, having not seen significant rainfall in eight months.
Months into the rainy season, Southern California is now experiencing moderate drought conditions, according to the U.S. Drought Monitor.
“We also had very good rainfall and snowfall in the past couple of years, so we had a lot of excess fuels and they were very dry,” said Tirtha Banerjee, an associate professor of civil and environmental engineering at UC Irvine. “Then we had this weather system that created these very fast-moving Santa Ana winds.”
Banerjee’s research has found that those strong wind gusts help loft and transport embers, which is “what’s responsible for most of the building damage,” he said.
“It’s not necessarily always this big wall of flame but rather embers transporting long distances and landing on some kind of fuel nearby or directly landing on a building.”
During intense windstorms, embers become fiery invaders of homes. Embers driven by raging winds through small openings or against exposed wood can be responsible for igniting a majority of fires in homes. During the Witch fire in 2007, in many cases the embers smoldered for hours before causing homes to burn.
In some cases in past firestorms, homes are destroyed from the inside out, according to firefighters, a clear sign that the fires were caused by embers within, not flames attacking the outside walls.
Homes that are set ablaze by embers can also then contribute to even more ember generation, Banerjee said. That’s typical with wildland-urban interface fires, which are often driven by a combination of structures and vegetation burning.
While Santa Ana winds regularly occur at this time of year, these particularly strong gusts came through complex topography and terrain that can help them gain speed and funnel them in unpredictable ways, said Alexandra Syphard, senior research ecologist at the nonprofit Conservation Biology Institute and adjunct professor at San Diego State University.
“When you’ve got winds like this, the fire is no longer spreading through the vegetation on the ground,” she said. “The fire is spreading through the air.”
The ember-driven nature of the wildfire can help explain why, in some neighborhoods, some homes remain standing next to homes that have burned to the ground. A home that is more fire resistant — with diligence paid to sealing up openings that can let embers in — can stand a better chance of surviving a cloud of embers.
It’s difficult to say the precise role that climate change may have played in these fires, but the climatic conditions that helped them grow so dramatically are consistent with what scientists expect to see in a warming world, said Noah Diffenbaugh, climate scientist at Stanford University.
“We have clear evidence that California is warming, along with the globe,” he said. “We know that warming increases the likelihood of highly flammable vegetation.”
Studies have shown that the population is growing in the wildland urban interface, especially in areas where the vegetation is highly sensitive to the effects of climate change, Diffenbaugh said.
“So there is this kind of double hazard of climate change and population growth in the areas that are most sensitive with regard to wildfire risk,” he said.
Sign up for Essential California
The most important California stories and recommendations in your inbox every morning.
You may occasionally receive promotional content from the Los Angeles Times.
