Santa Ana winds — “likely the strongest Santa Ana event we have seen so far this season” — will buffet the Southland amid sharply cooler temperatures Monday and combine with low humidity and dry vegetation to create a danger of wildfire through Tuesday, “the most dangerous fire weather conditions” in more than a year, the National Weather Service warned.
“Moderate to strong Santa Ana winds are expected to develop across most of Los Angeles and Ventura Counties late Sunday night through Tuesday, likely the strongest Santa Ana event we have seen so far this season.” The strongest winds are expected late Sunday night through Monday evening, “when damaging gusts of 60 to 80 miles per hour can be expected in the mountains, gusts of 50 to 60 mph in the wind-prone valleys, and gusts of 35 to 50 mph from the Ventura coast to Malibu and the Hollywood Hills,” said a National Weather Service statement.
“The downslope winds will bring rapid drying, with widespread single-digit humidity by late Monday morning, and continuing through Tuesday.”
The weather service also warned that “the moderate to strong Santa Ana winds coupled with very low humidities and very dry fuels will likely bring the most dangerous fire weather conditions we have seen since October 2019 to Los Angeles and Ventura counties.”
The NWS said that a “particularly dangerous situation” is expected in the San Gabriel mountains Monday afternoon and evening due to the unusual combination of damaging wind gusts of 60 to 75 miles per hour, single-digit humidity and extremely dry vegetation.
A red flag warning signifying a high risk of wildfire will be 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, and the L.A. Coastal zone, which extends from beach cities to the Hollywood Hills. In inland Orange County, the red flag warning went into effect at 2.m. Monday and will remain in force until 6 p.m. Tuesday.
Some of the strongest winds are expected along the Grapevine, according to the National Weather Service.
A wind advisory accompanying the red flag warning went into effect at 11 p.m. Sunday in much of the region, with the high winds and low humidity combining to elevate the fire danger despite relatively cool temperatures.
The NWS also noted that strong winds will create dangerous sea conditions, which could capsize or damage small and large vessels, and issued a gale warning, which will be in effect off the Southland coast from 3 a.m. to 3 p.m. Monday.
The county’s Office of Emergency Management said it will be prepared.
“Our emergency response officials are world-class and will stand ready to defend lives and property,” Director Kevin McGowan said on Sunday afternoon. “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.”
And the Los Angeles County Fire Department said it has boosted staffing in response to the red flag warning, with Fire Chief Daryl Osby ordering pre-deployment of resources throughout the County.
Despite the fire danger, freezing overnight temperatures are expected across the Antelope Valley Monday and Tuesday. A freeze warning will be in effect until 9 a.m. Monday in the Antelope Valley, and a hard-freeze watch from late Monday evening through Tuesday morning.
“Freezing conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing,” warned the NWS.
“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.”
A wind advisory will be in effect until 8 Monday morning in the San Gabriel Valley followed by a more serious high wind warning from 8 a.m. to 3 p.m. Monday. During the warning, north-to-northeast winds of 25 to 40 mph are expected, along with 65-mph gusts, mainly in the foothills and near the 210 Freeway corridor, warned the NWS, which added that 75-mph gusts are possible.
A high wind warning is also scheduled to be in effect until3 p.m. Tuesday in the San Gabriel Mountains amid winds of 30 to 45 mph and gusts of up to 70 mph , with the odd 80-mph gusts swirling on higher peaks. The strongest winds will blow along the Interstate 5 and Highway 14 corridors, forecasters said.
“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,” they said about San Gabriel Mountain conditions.
A high-wind warning is in effect until noon Tuesday in the Santa Monica Mountains and the San Fernando and Santa Clarita valleys, with northeast winds of 25 to 40 mph expected, along with gusts of 65-70 mph.
A less serious wind advisory is 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,” warned the NWS. “Tree limbs and temporary structures could be blown down and a few power outages may result.”
Also issued was a wind advisory that will be in effect, also until noon Tuesday, on Santa Catalina Island, where forecasters expect northeast-to-east winds of 20-30 mph gusting to 45 mph.
The NWS forecast sunny skies in L.A. County Monday and much cooler temperatures than those the region has experienced so far this fall — 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 will begin Tuesday, with highs in some communities being as much as 15 degrees higher than Monday come Sunday.
In Orange County, sunny skies were also 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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