Palisades and Eaton Fires Show Rising Dangers of Fast-Moving Fires

The Palisades and Eaton Fires show increased risks from moving fires

Who Stephanie Pappas edited by Andrea Thompson

The Palisades and Eaton Fires engulfed thousands of acres across the Los Angeles area in a matter of hours and forced the evacuation of tens of thousands of residents, some of whom had to abandon their cars and flee on foot. At least five people died in the fires on Wednesday evening.

Fast moving fires, Santa Ana driven by strong windsthey are part of an unfortunate trend. according to a paper published in science October 2024, average peak The daily rate of fire growth in the US West doubled Between 2001 and 2020. The average growth rate in California increased by 398%. “Fires are burning much faster in California,” says Jennifer Balch, a fire ecologist at the University of Colorado Boulder who led the study.

That study didn’t investigate why flash fires have become more common, but the reason is likely the same reason why the U.S. West is more prone to wildfires in general, Balch says. “When we warm the climate and make the fuels very dry we are making it very easy for fire to spread,” he says.

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That’s troubling, Balch says, because such fires are actually the most destructive. Although large fires often receive more attention, speed matters more than size when it comes to damage. Balch and his colleagues discovered that in the 21st century In the first two decades of the 20th century, 78% of the structures destroyed by fire in the United States burned in rapid fire. In fact, a growth rate of more than 4,000 acres per day was one of the best predictors of whether a fire would cause extensive damage to homes and other buildings.

“When these fires happen, they can quickly affect communities that have little time to prepare or evacuate,” says John Abatzoglou, a climate scientist at the University of California, Merced, who was not involved in the study. “And that’s effectively what we’re seeing with some of these fires in Southern California.”

The largest of the fires, the Palisades Fire, has burned more than 15,000 acres since it started Tuesday, according to the California Department of Forestry and Fire Protection. The Eaton Fire is behind us: it has burned 10,600 acres since Tuesday. Two other wildfires, the Hurst and Woodley Fires, also broke out on Tuesday and Wednesday, respectively, and have collectively burned more than 700 acres, with the majority of that number attributed to the Hurst Fire.

This rapid destruction occurred during a dry southern California winter following a dry fall, and these conditions followed a particularly wet winter last year. It’s the perfect recipe for a big, fast fire, Abatzoglou says, because a wet year boosts the growth of highly flammable shrubs and small grasses, and a dry year afterward turns those plants into crispy matches, ready to catch fire. “Weather bites contribute to the likelihood of very large, fast-moving wildfires,” says Katharine Hayhoe, a climate scientist at the Nature Conservancy and Texas Tech University who studies climate impacts. Rising temperatures attributed to greenhouse gas emissions have disrupted natural fire patterns worldwide, and reducing emissions is important to mitigate the effects.

With wind-driven fires like the Santa Anas — which gusted nearly 90 miles per hour in southern California on Tuesday night — embers drift ahead of the moving fire front, sparking new fires faster than they can be extinguished. These embers spell disaster for homes, says Yana Valachovic, county director of the University of California Cooperative Extension in Humboldt and Del Norte counties. “Most of our homes are not built or renovated to be fireproof,” he says.

Santa Ana winds are predicted to decrease in fall and spring in a warming world, According to 2019 researchbut they are not expected to decrease in intensity, and “you only need one Santa Ana wind event that occurs in places where the fuels are really dry to cause this kind of disaster,” says Abatzoglou. Southern California’s wet season is compressing, with less precipitation in the fall and spring. This extends the fire season and coincides with the typical Santa Ana wind season, which runs from October to January.

“Winter fire has to be an oxymoron,” says Balch. But LA’s experience has been similar to another wind-driven event in Colorado: the Marshall Fire, which started on December 30, 2021. A warm, dry winter and a high wind event caused the fire to burn over three miles in one hour. 1,000 structures burned and two people killed.

The University of California Agriculture and Natural Resources Fire Network has created one checklist of what to do if you are near an active fire that is not yet under an evacuation order. Simple steps like moving flammable items away from exterior walls, sealing vents and closing pet doors can help harden a home against ignition, Valachovic says. Previous steps include replacing standard air covers with fine mesh that resists embers, clearing vegetation within five feet of home walls, and building the last few feet of wood fence lines with a noncombustible material that won’t move fire directly toward the home.

The Palisades and Marshall Fires hit suburban areas, often considered to be at low fire risk. But about 1 million homes in the U.S. were within a fire perimeter in the past two decades, and 59 million more They are 0.6 kilometers from the perimeter of past firessays Balch. “That’s a big risk we’re living in,” he added.