As drought worsens in Southern California, Santa Ana winds bring 'extreme fire conditions'
The National Weather Service has issued a red flag warning for Los Angeles and parts of Ventura County through Thursday evening, meaning that conditions for wildfires will be at their highest thanks to low humidity, an ongoing drought and the arrival of strong Santa Ana winds
"HEADS UP!!! A LIFE-THREATENING, DESTRUCTIVE, Widespread Windstorm is expected Tue afternoon-Weds morning across much of Ventura/LA Co. Areas not typically windy will be impacted," the National Weather Service in Los Angeles said in a message posted to social media on Monday.
The areas "of greatest concern" include the San Gabriel, Santa Susana and Santa Monica Mountains and foothills, as well as the San Fernando Valley, Pasadena, Burbank, Hollywood, Beverly Hills, Simi Valley, Sylmar, Porter Ranch, Altadena, La Crescenta and Malibu, the National Weather Service said.
Wind gusts between 50-80 miles per hour are expected across the region, with gusts of up to 100 mph possible for some mountainous regions that haven’t seen significant rainfall in months.
“A Red Flag Warning means that critical fire weather conditions are either occurring now, or will shortly. Use extreme caution with anything that can spark a wildfire,” the National Weather Service said. “Residents near wildland interfaces should be prepared to evacuate if a wildfire breaks out.”
High wind watches have also been posted in the mountains of Riverside and San Diego counties, which will have an elevated risk of wildfire.
What are Santa Ana winds?
For residents of Southern California, Santa Ana winds are nothing new.
“Santa Ana winds are dry and warm (often hot) winds in the Southern California area that blow in from the desert — which includes the Great Basin of the western United States, incorporating Nevada and part of Utah,” Robert Fovell, a professor of atmospheric and oceanic sciences at UCLA, said in an FAQ posted to the university’s website.
The winds can blow any time when the Great Basin becomes cooler than Southern California. Most typically, that occurs between September and May.
“The Great Basin resides at a higher elevation than the L.A. Basin, which is near sea level. The air flowing into Southern California, forming the Santa Ana winds, is subsiding. When air descends, it is compressed, and its temperature rises,” Fovell explained.
Author Joan Didion introduced many Americans to the famous winds in her 1969 essay “The Santa Anas.”
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“It is hard for people who have not lived in Los Angeles to realize how radically the Santa Ana figures in the local imagination. The city burning is Los Angeles's deepest image of itself,” she wrote.
Drought continues to worsen in the south
The warnings come as much of the southern half of the state has had a drier than normal weather pattern. The affected areas are currently experiencing moderate drought conditions, according to the U.S. Drought Monitor, and Ventura, Los Angeles, Orange, San Bernardino and Riverside counties are abnormally dry or worse.
But that hasn’t been the case for the entire state.
“Portions of San Diego County have seen their driest start to the season (and 9-month period overall) in over 150 years; the contrast between (anomalously wet) NorCal and (record dry) SoCal is even more anomalous than either the northern wet or southern dry anomalies on their own,” UCLA climate scientist Daniel Swain wrote on his blog, Weather West. “It is truly a matter of the precipitation 'haves' and 'have nots' at the moment—and there is no real prospect for this to change in the short term; even in the long term, it remains possible this overall dipole persists for the rest of the season (though hopefully with less extreme intensity).”
With such dry conditions in place in the southern half of the state in combination with strong Santa Ana winds, residents of Southern California are bracing for the worst.
“Here we go again. Another wind event. … So, fire concerns are going to be the main story for us,” KTLA meteorologist Henry DiCarlo said Monday.
