Why the Los Angeles-area wildfires spread so fast

Multiple homes burned along a Malibu street as the Palisades Fire swept through several neighborhoods. (Video courtesy: Annestacia Komarovsk via Storyful)

LOS ANGELES – A series of wildfires that erupted around Los Angeles County on Jan. 7 were exacerbated by extreme weather conditions, some of which had been building for months.

Fires such as the Palisades, Eaton and Hurst have destroyed tens of thousands of acres and damaged thousands of homes.

The severity of the event was made more likely by a combination of climate conditions, such as dry vegetation and the lack of significant rainfall since the spring.

A delayed start to the winter rainy season, combined with hurricane-force wind gusts and low humidity levels, contributed to the “particularly dangerous” fire conditions.

Santa Ana winds are relatively common in Southern California, driven by a high-pressure ridge over the western U.S. that forces winds through the region’s hills and mountains. 

Typical wind gusts range from 40-60 mph, but they occasionally reach hurricane-force gusts (at least 74 mph), as was the case during the most recent event.

Santa Ana Winds map

(FOX Weather)

LOS ANGELES METRO ENGULFED BY DEADLY APOCALYPTIC WILDFIRES FUELED BY HURRICANE-FORCE WIND GUSTS

Winds gusted up to 100 mph in La Cañada, California, while Escondido and Van Nuys experienced tropical storm-force gusts (at least 39 mph).

These extreme winds, combined with dry conditions, led to widespread power outages and prompted meteorologists to issue warnings about “life-threatening” conditions, independent of the fire activity.

The winds, alongside drought conditions, low humidity and dry soil, significantly heightened the wildfire threat.

Similar conditions were seen in the Hawaiian Islands in 2023, where wildfires on the western sides of the mountains destroyed more than 2,000 structures and led to the deaths of 102 people. 

Like California, Hawaii often experiences precipitation during the winter and spring, with arid conditions prevailing on the lee side of the mountains – home to many of the region’s largest population centers.

Communities such as the Los Angeles Basin and San Diego, which are located on the lee side of mountain ranges, are home to more than 10 million people combined.

The population and vegetation make the region susceptible to wind-driven embers that flew for miles from the large infernos, igniting hundreds of fires during the recent firestorms.

Videos and photos from the Eaton Fire and the Palisades Fire showed embers flying for miles away from the heart of the blazes.

Southern California Fire Map

(FOX Weather)

WATCH: LOS ANGELES HOME COLLAPSES LIVE ON FOX WEATHER AS WILDFIRES RAGE IN SOUTHERN CALIFORNIA

Authorities have not yet determined what triggered the fires. 

The 2023 Hawaiian wildfires and California’s 2018 Camp Fire were linked to utility lines. Utility providers in both states implement power shutoff programs on days with extreme wildfire potential, but it is unclear whether any shutoffs occurred in neighborhoods around Los Angeles County before this week’s disaster. 

Utility lines and other human sources will undoubtedly be a focus of investigators as they search for the cause of the flames.