Powerful Santa Ana winds and rising temperatures will combine with low humidity starting Thursday to create critical wildfire conditions across much of Los Angeles County, with forecasters warning of potentially damaging gusts and an elevated risk of rapidly spreading fires through Saturday.
The National Weather Service issued red flag warnings of critical fire danger for much of Los Angeles County beginning at 6 a.m. Thursday and continuing until 8 p.m. Saturday.
Forecasters noted that winds of 40 to 50 mph were already recorded in some mountain areas Wednesday morning, along with gusts of 25 to 35 mph in the western San Fernando Valley.
“The first Santa Ana event for the season is going to be a strong one,” according to the NWS, which said winds are expected to peak on Friday.
“During that peak period, wind gusts across the LA/Ventura mountains are expected to reach as high as 70 mph while the LA/Ventura valleys and Ventura coastal areas peak at around 55 mph,” forecasters said.
Temperatures are also expected to rise with the onset of the Santa Ana winds, with most coastal areas reaching into the 90s by Friday. Valleys are expected to be in the mid-80s to mid-90s, but there’s a slight chance some areas could reach triple-digits, forecasters said.
Red flag warnings will cover the Santa Monica Mountains Recreational Area, San Gabriel Mountains, the Golden State (5) and Antelope Valley (14) freeway corridors, Antelope Valley foothills, the Malibu Coast, Calabasas and the Santa Clarita, San Fernando and San Gabriel valleys.
In addition to the gusting winds, forecasters said mountain areas could experience humidity levels falling to between 8% and 20%. Other areas could see winds of 20 to 30 mph, gusting to 50 mph, with humidity dropping as low as 5%.
The NWS also issued wind advisories from 6 a.m. Thursday through 8 p.m. Friday for the Malibu Coast, the Santa Clarita and San Fernando valleys, and the Eastern Santa Monica Mountains Recreational Area.
A high wind warning will be in effect from Thursday morning through Friday evening for the Western Santa Monica Mountains Recreational Area, the San Gabriel Mountains and the 5 and 14 freeway corridors. A wind advisory will be in effect for the Malibu coast.
“A red flag warning means that critical fire weather conditions are either occurring now, or will shortly,” forecasters said. “Use extreme caution with anything that can spark a wildfire. Residents near wildland interfaces should be prepared to evacuate if a wildfire breaks out.”
Heat advisories will take effect at 10 a.m. Thursday and continue through Saturday for the Malibu Coast, Los Angeles County beaches, Palos Verdes Hills and the Inland Coast, including downtown Los Angeles.
The hot, dry and windy conditions could prompt Southern California Edison to implement public safety power shutoffs to reduce the risk of power lines sparking wildfires.
According to SCE’s website, more than 89,400 customers in Los Angeles County were being considered for possible power shutoffs as of Wednesday afternoon, but no such shutoffs had actually occurred yet.
Malibu officials said Tuesday that SCE had notified the city of possible shutoffs beginning as early as midnight Thursday on the Cuthbert, Galahad, Maguire and Merlin circuits in central and western Malibu.
Residents were urged to charge electronic devices, prepare emergency supplies, review evacuation routes and secure loose outdoor items.
The NWS also cautioned drivers about dangerous crosswinds, particularly on elevated roadways.
Meanwhile, dangerous surf conditions will continue along Los Angeles County beaches, where a beach hazards statement remains in effect through Thursday afternoon.
Forecasters said long-period swells from the west and south, combined with elevated morning tides of 6.5 to 7 feet, could cause minor coastal flooding, particularly in low-lying beach and harbor areas.
The coastal hazards follow several days of damaging surf and flooding associated with the remnants of former Tropical Storm Rachel.
The weather service said Santa Ana winds could persist into Saturday, although conditions are expected to weaken over the weekend.
Temperatures will remain above normal through Sunday before a significant cooling trend begins early next week, according to forecasters.