Southern California braces for strongest Santa Ana winds of the year

LOS ANGELES, CA - NOVEMBER 09: The passing storm left the Southland with clear views such as this looking north along Avalon Boulevard in South Los Angeles. The drenching storm set rainfall records in parts of the area, with forecasters saying some light Santa Ana winds will push temperatures up slightly during daylight hours later this week, but chilly temperatures could still prevail at night. Photographed on Wednesday, Nov. 9, 2022 in Los Angeles, CA. (Myung J. Chun / Los Angeles Times)
A red flag warning will be in effect starting Wednesday for parts of Los Angeles County, including the mountains, according to the National Weather Service. (Myung J. Chun / Los Angeles Times)

Southern California is bracing this week for what could be the strongest Santa Ana winds of the year, raising concerns around both fire dangers and cold temperatures, according to experts.

“Today is the calm before the gusty winds are expected,” David Sweet, a meteorologist with the National Weather Service in Oxnard, said Monday.

“This is going to be the biggest event this season,” Sweet added.

Moderate Santa Ana winds are expected to develop Tuesday morning and continue throughout the day, with gusts ranging from 35 mph to 45 mph, according to the National Weather Service. High winds will continue through Wednesday. Paired with low humidity, the high winds prompted the National Weather Service to issue a red flag warning for fire danger most of the day Wednesday for much of Ventura County and western areas of Los Angeles County, including Malibu.

A red flag warning is issued when extreme fire behavior could occur because of high winds and low humidity.

Gusts will peak Wednesday morning, with “damaging northeast winds" expected at 75 mph, Sweet said. Temperatures are forecast to be in the low 70s, and relative humidity will be down between 10% to 20%, Sweet added.

With conditions ripe for rapid fire growth, weather experts initially issued a fire weather watch but, by Monday afternoon, warned that low humidity raised the danger of brush fires spreading quickly. The red flag warning for western L.A. County and the majority of Ventura County was issued for 7 a.m. to 7 p.m. on Wednesday.

A watch means critical fire weather conditions are possible but not imminent or occurring, weather experts said.

"If fire ignition occurs, there could be rapid spread of wildfire that would lead to a threat to life and property," the National Weather Service warned in an alert.

Weather experts have warned of downed power lines and trees, and advise securing any outdoor furniture, including trampolines.

The conditions this week have also led to concerns about cold weather expected for parts of L.A. County.

“With very dry air in place, the temperature tends to drop like a rock overnight,” said Sweet, adding the week did not look “terribly cold.” But the wind could drop off in places including Ojai in Ventura County and the Antelope Valley, where temperatures might sink to the mid-30s any night this week, Sweet said.

Muntu Davis, the Los Angeles County public health officer, issued a cold weather alert on Sunday for several areas, including in the Santa Clarita Valley, in effect through Tuesday; the Mt. Wilson area, in effect through Wednesday; and Lancaster, in effect through Friday.

Davis said seniors, children and those with disabilities or medical needs are especially vulnerable, and reminded the public not to heat their homes with stoves, ovens or barbecues because of the risk of carbon monoxide poisoning. The Los Angeles Homeless Services Authority has a program for those who need warm shelter, Davis said.

Areas below the Cajon Pass and through the Inland Empire, including Ontario and Corona, and extending to the Santa Ana mountains and foothills, including in Tustin and Orange, could have gusts up to 70 mph. Winds will reach about 50 mph in most urban locations, said Dan Gregoria, a meteorologist with the National Weather Service in San Diego.

Winds are expected to subside Wednesday evening. A weaker wind event is forecast for later this week, Gregoria said.

This story originally appeared in Los Angeles Times.