A red flag warning signifying a high wildfire risk will be in effect Thursday and Friday in most of L.A. and Orange counties because of strong winds and single-digit humidity levels, forecasters said.
Southern California Edison warned it could cut power to transmission lines Thursday in some areas at high risk for brush fires. They include Malibu, the Santa Clarita Valley, Agoura Hills, Altadena, the Santa Ana foothills communities in Orange County and neighboring communities. About 53,000 business and residential customers could have their power cut if high winds pose a risk of downing electrical transmission lines and sparking brush fires. The utility notifed customers and cities of the possible outages.
The red flag warning will go into effect at 10 Thursday morning and expire at 10 Friday night. It will be in force in the San Gabriel and Santa Monica mountains, the Angeles National Forest, the San Fernando, San Gabriel and Santa Clarita valleys, L.A. County Beach cities, metropolitan Los Angeles, the Downtown area, the Hollywood Hills, several areas of Ventura County, and inland Orange County, according to the National Weather Service. No warning was issued for the Antelope Valley.
“The OCFA will be up-staffing with additional resources and augmenting all initial attack fire responses,” the Orange County Fire Authority tweeted Thursday morning.
A strong Santa Ana Wind event will get underway Thursday morning and persist through Friday evening, the NWS said in a statement. Peak winds likely will occur overnight, with a potential of gusts of 40-50 miles per hours in the valleys and along the coast, and 60-70 mph in the mountains, it said.
There will be a break in the wind event Saturday night, but another Santa Ana event is expected Sunday through Monday, although it will not be as strong as Thursday’s, forecasters said, adding that a fire weather watch, which is a little less serious than a red flag warning, may be needed for the second set of Santa Anas.
Forecasters expect winds of 20-30 mph accompanied by 55 mph gusts in the San Gabriel Mountains, the Angeles National Forest and the Santa Monica Mountains, possibly increasing to 30-40 mph Thursday evening, with 70 mph gusts. The humidity in those areas will dip to 5-10 percent, they said.
The wind will blow at 15-25 mph and gust to 40 mph in Los Angeles amid humidity levels of 6-12 percent, and at 25-35 mph with 55 mph gusts in the Santa Ana Mountains in Orange county, with isolated 65-mph gusts possible.
“If fire ignition occurs, conditions may be favorable for rapid fire spread and extreme fire behavior, which would threaten life and property,” warned an NWS statement.
The NWS forecast partly cloudy skies in L-A County Thursday and highs of 61 on Mount Wilson; 68 in Palmdale; 69 in Lancaster and Avalon; 71 in Saugus; 76 at LAX; 77 in Downtown L.A., Pasadena, San Gabriel and Woodland Hills; and 78 in Burbank.
Sunny skies were expected in Orange County, along with highs of 60 on Santiago Peak; 71 on Ortega Highway at the 2,600-foot level; 75 in San Clemente, Laguna Beach and in Fremont Canyon; 76 in Newport Beach; 77 in Trabuco Canyon; 78 in Yorba Linda and Anaheim; 79 in Irvine and Mission Viejo; and 80 in Fullerton.
Temperatures will remain in the high 70s and low 80s in L.A. and Orange counties for several days.