Terrible fires raging through densely populated areas of southern California were made worse by an unusual, monthslong lack of rain across the region.
The flames have forced more than 100,000 people out of their homes and forced many more to remain alert to flee on a moment’s notice. Flames whipped up earlier this week when ferocious Santa Ana winds roared across the region.
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Explainer: Santa Ana Winds
A high-end Santa Ana wind event this week served as the catalyst that helped ignite several intense wildfires throughout the Los Angeles metropolitan area.
Wind gusts of 100-150 km/h combined with exceptionally dry air made conditions favourable for the spark and fast spread of devastating wildfires.
The Palisades and Eaton fires are the largest blazes, according to data released by Cal Fire. The Palisades Fire grew to about 7,000 hectares on Thursday, with the Eaton Fire close behind at nearly 4,300 hectares. Both fires remained at 0 percent containment on Thursday afternoon.
Major disasters occur through a confluence of factors—and wildfires are no exception. Variables like weather conditions, fuel availability, population density, and geography all play a role in the severity and intensity of wildfires.
The lack of rain here is a serious problem.
Los Angeles Rain 2024
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Los Angeles experiences a rainy season and a dry season. The rainy season generally begins in early October and continues through late April. The city averages very little rainfall between May and September.
2024 began with a bang across southern California as uncharacteristic rains swept into the region. Los Angeles recorded 254 mm of rain in February, making it the city’s third-rainiest February on record.
This surplus of rainfall fed excess vegetation growth throughout the region, allowing brush to flourish as occasional bouts of rain continued into the early spring.
And then the tap shut off.
California Percent of Normal Precip 2024-2025
Southern California’s atmospheric fortunes reversed in a hurry, leaving the region facing a tremendous rainfall deficit that’s rivalled some of the driest years on record.
Los Angeles has only recorded 0.8 mm of rain since July 1, 2024. That represents just 1.25 percent of the city’s normal precipitation over the past 180 days.
The excessive dryness across southern California stands in stark contrast to the bountiful precipitation they’ve seen in the northern half of the state over the same time period. The town of Eureka has seen 150 percent of its normal rainfall since July after a series of atmospheric rivers washed ashore.
All the growth from last year’s rains dried out amid Los Angeles’ monthslong stretch with no meaningful precipitation—quite literally laying the groundwork for this week’s awful fires.
While many factors played into the intensity and severity of these wildfires, this kind of an all-or-nothing precipitation pattern is in line with what we’d expect to see as the climate changes. “Research shows that changes in climate create warmer, drier conditions, leading to longer and more active fire seasons,” NOAA reported in 2023.
Header image courtesy of NASA/NOAA/MODIS.
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