December wildfires are now a thing

This story is original appeared on Top country news It is part of Climate Office cooperation.

In Southern California, wildfires in December are somewhat uncommon but not completely out of the ordinary. This year, extremely dry conditions and strong Santa Ana winds have created the perfect recipe for dangerous late-year fires.

On the night of December 9th Franklin Fire It broke out in the hills above Malibu, tearing throughAbout 3,000 acres in just 24 hours. As of midday on December 12, the fire was less than 10 percent contained, with just over 4,000 acres burned and at least 4,000 acres burned. Seven structures.

last month, Mountain fire The fire burned under similar conditions in nearby Ventura County, expanding to 1,000 acres in the first hour. Within two days it was over 20,000 acres. 240 structures were destroyed before firefighters were able to bring them under control in early December.

It had not rained yet, not since the mountain fire, and not throughout 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 — are routinely active in the fall and winter. But what is less normal is the lack of rainfall Sweeping Southern California at the moment, although the area is not technically in a region drought yet.

The weather station in downtown Los Angeles has registered Only 5.7 inches of rain has fallen this year, and not even a quarter-inch fell in December, which is usually the middle of the region’s rainy season. Most years would have had three or more rainy days by this time, enough to reduce some wildfire risk; About 90 percent of the rain falls in the region Come Between October and the end of April.

“We are still waiting for the start of the rainy season in that part of the state, which should significantly wet the fuels and put an end to the risk of large fires,” he said. John Apatzoglouprofessor of climatology at the University of California, Merced.

In wetter years, the monsoon presents less fire risk. But now, “when ignitions hit the wind,” Apatzoglou says, the landscape is ripe for fire. Dry grass and shrubs are ready for burning, and Fire hazard The Los Angeles County Fire Department’s forecast for December 11, the day the fires increased the most, was high or very high throughout the Los Angeles Basin, Santa Monica Mountains and Santa Clarita Valley. “It hasn’t rained yet this season in Southern California,” he said. Daniel Swaina climate scientist at the University of California. “That’s the key. That’s the real kicker.”

High winds combined with dry vegetation aren’t just a problem for Southern California. Dry conditions increase the risk of wildfires across the country – during a drought East CoastFire seasons in spring and fall, for example. Winter fires broke out elsewhere in the West: fast-moving Colorado Fire Marshall The blaze broke out on December 30, 2021, and went from a small grass fire to a suburban conflagration — which eventually burned more than 1,000 homes — in just one hour.