This story is basically appeared on high country news and is part of climate desk Collaboration.
In Southern California, wildfires in December are somewhat unusual but not completely out of the ordinary. And this year, extremely dry conditions and strong Santa Ana winds created the perfect recipe for dangerous late-year fires.
on the night of 9th December franklin fire Sparks flared in the hills above Malibu, Tear outNearly 3,000 acres of land in just 24 hours. By the afternoon of December 12, the fire was less than 10 percent contained, having burned and destroyed at least 4,000 acres of land. seven structures,
last month, mountain fire It ignited under similar conditions in nearby Ventura County, growing by 1,000 acres in the first hour. Within two days it exceeded 20,000 acres; 240 structures were destroyed before firefighters brought it under control in early December.
And it still hasn't rained — not since the Mountain Fire, nor during the entire fall.
It's true that Santa Ana winds – dry winds that blow from the high desert to the coast and bring low humidity, sometimes less than 10 percent – increase regularly in the fall and winter. But what is less common is the lack of rainfall. entertaining Southern California right now, even though the area isn't technically Dry As yet.
Downtown Los Angeles Weather Station recorded Only 5.7 inches of rain has fallen this year, and not even a quarter of an inch has fallen in December, which is typically the middle of the region's wet season. Most years will have seen three or more wet days by this time, enough to prevent wildfire risk; About 90 percent rainfall of the area comes Between October and the end of April.
“We are still waiting for the onset of the rainy season in that part of the state, which will meaningfully wet the fuels and eliminate the threat of major fires,” he said. John AbatzoglouProfessor of Climate Science at the University of California, Merced.
In wet years, there is less risk of fire in windy weather. But now, “when ignition and wind collide,” as Abatzoglu puts it, the landscape is ripe for fire. Dry grass and bushes are ready to burn, and fire danger On December 11, the fire was forecast by the Los Angeles County Fire Department to be at high or very high levels throughout the Los Angeles Basin, Santa Monica Mountains, and Santa Clarita Valley. “It hasn't rained in Southern California yet this season,” said daniel swainA climate scientist at UCLA. “This is the key. That's the real kicker.”
The high winds that come with bone-dry vegetation aren't just a problem for Southern California. Wildfire risk increases across the country during dry conditions east coastFor example, the spring and fall fire seasons. And winter fires have raged elsewhere in the West: growing rapidly in Colorado marshal fire On December 30, 2021, the spark grew from a small grass fire to a suburban blaze – which ultimately burned more than 1,000 homes in just one hour.