Strong Santa Ana winds buffeted the Southland amid sharply cooler temperatures Monday that, when combined with low humidity and dry vegetation, were creating “the most dangerous fire weather conditions” in more than a year, the National Weather Service warned.
“The combination of a strong offshore pressure gradient, strong upper level wind support, and significant cold air advection is producing the strongest Santa Ana wind event we have seen so far this season, with the most dangerous fire weather conditions we have seen since October 2019,” according to the National Weather Service.
Windy conditions were expected to last through Tuesday in most of Los Angeles and Ventura counties, with the most damaging gusts expected Monday.
Recorded gusts were in the range of 60 to 90 mph in the mountains and foothills Monday, according to the NWS, which said one gust was clocked at 96 miles per hour in the San Gabriel Mountains south of Santa Clarita.
Into Monday evening, the forecast called for damaging wind gusts of 60 to 75 mph to continue in the mountains of Los Angeles and Ventura counties, and 50 to 60 mph in the valleys and foothills. Wind gusts of 35 to 50 mph are expected across the Ventura coast and Malibu to Hollywood Hills.
“The downslope winds will bring rapid drying, with widespread single-digit humidity … continuing through Tuesday,” the weather service said as a red flag warning — signifying a high risk of wildfire — went into effect at 11 p.m. Sunday in much of the region and was expected remain in force until 6 p.m. Tuesday in the San Gabriel and Santa Monica Mountains, the Angeles National Forest, the Santa Clarita, San Fernando and San Gabriel valleys, inland Orange County and the Los Angeles coastal zone, including beach cities.
“New fire ignitions in Los Angeles and Ventura counties will have likely have very rapid fire growth, extreme fire behavior, and long range spotting, resulting in a significant threat to life and property,” NWS officials said.
Concerns about wildfires prompted Southern California Edison to shut off power to hundreds of customers in Los Angeles and Orange counties in a precautionary move to prevent electrical equipment from sparking blazes.
As of midday, nearly 1,800 SCE customers in Los Angeles County had their power cut due to the precautionary measures, primarily in the Santa Clarita and Antelope Valley areas. More than 400 Orange County customers were affected.
Overall, SCE as of midday was reporting more than 14,000 Los Angeles County customers without power amid the wind event, and nearly 8,000 in Orange County. The Los Angeles Department of Water and Power was also responding to power outages across the city, including the Brentwood, Hollywood and Rancho Park areas.
In Orange County, a wildfire reported at 6:47 a.m. raced across terrain in the Santiago Canyon area, forcing mandatory evacuations in the Orchard Hills area, threatening structures and blocking key roadways through the region. The blaze erupted in the area of Santiago Canyon and Silverado Canyon roads and was estimated at about 4,000 acres by 1 p.m.
Another Orange County fire was reported about 1 p.m. in Corona, threatening homes in Yorba Linda as it quickly scorched 100 acres just off Green RIver Road and the Riverside (91) Freeway.
The Los Angeles County Fire Department boosted staffing in response to the red flag warning, with Fire Chief Daryl Osby ordering pre-deployment of resources throughout the county.
Office of Emergency Management Director Kevin McGowan said Los Angeles County is prepared.
“Our emergency response officials are world-class and will stand ready to defend lives and property,” he said. “We need collaboration from all residents who live in L.A. County to stay safe as a region. We must all do our part by staying informed and being ready to evacuate at a moment’s notice, especially if you live in canyon, mountain or foothill communities.”
A wind advisory accompanying the red flag warning went into effect at 11 p.m. Sunday in much of the region. It was scheduled until noon Tuesday along the L.A. County coastal zone, which includes Long Beach, Malibu, Santa Monica, Beverly Hills, metropolitan Los Angeles, the downtown area, and the Hollywood Hills.
“Gusty winds will blow around unsecured objects and make driving difficult (in the coastal zone), especially for high-profile vehicles,” the NWS warned. “Tree limbs and temporary structures could be blown down and a few power outages may result.”
Some of the strongest winds were expected along the Grapevine, according to the National Weather Service.
High wind warnings were issued through 3 p.m. Monday in the San Gabriel Valley, mainly in the foothills and near the 210 Freeway corridor, as well as through 3 p.m. Tuesday in the San Gabriel Mountains as strong and erratic waves of wind swirled on higher peaks and strong gusts were expected to blow along the Interstate 5 and Highway 14 corridors, forecasters said. A high-wind warning also was in effect until noon Tuesday in the Santa Monica Mountains and the San Fernando and Santa Clarita valleys.
“Damaging winds will blow down large objects such as trees, power lines and temporary structures. Power outages are expected. Travel will be difficult, especially for high-profile vehicles,” the NWS said about San Gabriel Mountain conditions.
A wind advisory also was in effect until noon Tuesday on Santa Catalina Island, where forecasters expected northeast-to-east winds of 20-30 mph gusting to 45 mph.
Strong winds also create dangerous sea conditions, which could capsize or damage small and large vessels, and the National Weather Service issued a gale warning, which will be in effect off the Southland coast from 3 a.m. to 3 p.m. Monday.
Freezing overnight temperatures also were expected across the Antelope Valley on Monday and Tuesday. A freeze warning was in effect until 9 a.m. Monday in the Antelope Valley, and a hard-freeze watch was declared through Tuesday morning.
“Freezing conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing,” the NWS said. “To prevent freezing and possible bursting of outdoor water pipes, they should be wrapped, drained, or allowed to drip slowly. Those that have in-ground sprinkler systems should drain them and cover above-ground pipes to protect them from freezing.”
Temperatures Monday night were expected to dip to the upper 40s to mid 50s in the Los Angeles area, San Gabriel Valley, San Fernando Valley and Santa Monica Mountains. Santa Clarita will be cooler, with lows in the upper 30s to mid 40s. And the Antelope Valley could be as cold as the mid 20s to mid 30s.