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.
Gusts mostly in the range of 60 to 80 mph were expected in the mountains and foothills, according to the NWS, which said gust up to 96 miles per hour were clocked Monday morning in the San Gabriel Mountains south of Santa Clarita. Gusts of 45 to 65 mph were forecast in valleys and wind-prone coastal areas.
“The downslope winds will bring rapid drying, with widespread single-digit humidity by late Monday morning, and 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, which extends from beach cities to the Hollywood Hills.
“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.
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 2,000 acres by 11 a.m.
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.”
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.
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.”
Despite the chill, the NWS forecasted sunny skies in Los Angeles County Monday with highs of 52 degrees on Mount Wilson; 63 in Palmdale; 64 in Lancaster; 66 in Saugus; 70 in Burbank; 71 in Avalon, Pasadena, and San Gabriel; 72 at LAX; 73 in Woodland Hills and Downtown L.A.; and 74 in Long Beach. A warming trend was expected to begin Tuesday.
In Orange County, sunny skies also were in the forecast, along with highs of 46 on Santiago Peak; 58 on Ortega Highway at 2,600 feet; 63 at Fremont Canyon; 66 at Trabuco Canyon; 71 in San Clemente and Laguna Beach; 68 in Yorba Linda; 69 in Mission Viejo; 71 in Anaheim; and 72 in Irvine and Fullerton. By Sunday, inland communities will be in the low 80s.
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