Gusty Santa Ana winds and “very low humidity” will combine to create “widespread critical fire weather conditions” in much of the Southland from early Thursday through Friday evening, and thousands of residents could be subject to precautionary power outages.
Wind gusts of between 45 and 70 mph are expected from mid-morning Thursday to mid-afternoon Friday as humidity levels fall to between 3 and 10 percent, according to the National Weather Service.
Given an abundance of dry vegetation, “critical fire weather conditions are expected,” NWS forecasters said in a statement.
A red flag warning will be in force in the San Gabriel and Santa Monica mountains and the Angeles National Forest — areas where winds blowing at a sustained 25 to 45 mph are expected, along with 70 mph gusts and humidity levels of 3-10 percent — from 3 a.m. Thursday until 6 p.m. Friday.
The warning will also be in force at the same time in the San Fernando, Santa Clarita and San Gabriel valleys, along the L.A. County coast and in metropolitan Los Angeles, including downtown L.A. Additionally, it will be in effect in much of Ventura County, including the Los Padres National Forest adjoining the Angeles National Forest, and in coastal Orange County from 3 a.m. Thursday until 8 a.m. Friday.
“If fire ignition occurs, conditions may be favorable for extreme fire behavior, which would threaten life and property,” according to the NWS.
The Santa Ana winds result from high pressure over Nevada, said NWS meteorologist Rich Thompson, while the low humidity is caused by cold dry air and a drying-out effect that occurs when winds blow across mountain slopes.
Southern California Edison cautioned that thousands of customers throughout its service area could lose power due to “Public Safety Power Shutoffs” aimed at reducing fire risks. The shutoffs are conducted during extreme fire conditions — de-energizing power lines that might be damaged in high winds and spark wildfires. As of Wednesday morning, no shutoffs had been ordered in SCE’s service area, but nearly 174,000 customers were in areas that are “under consideration” for power cuts.
In Los Angeles County, there are roughly 49,000 customers facing possible cuts, primarily in the northern reaches of the county such as Lancaster, Palmdale, Santa Clarita and areas such as Acton, Agua Dulce, Lake Hughes and Canyon Country. La Crescenta/Montrose, Malibu, Chatsworth and San Fernando are also in the potentially affected area.
In Orange County, about 7,250 customers in Rancho Santa Margarita, Orange and North Tustin are in potential power-cut areas.
Malibu officials said Tuesday that SCE had given the city a 48-hour notice that a Public Safety Power Shutoff may be implemented that could affect Western Malibu beginning at 9 p.m. Thursday and continuing until 9 a.m. Friday. The city urged people who are medically dependent on electricity service to consider staying in another area until conditions change.
Edison urged residents to check on family members and neighbors who may need assistance in case of a power outage. If a PSPS is implemented, once hazardous conditions have passed it could take 24 to 72 hours to re-energize circuits because SCE must first inspect all power lines in the affected area to ensure they are safe to re-energize.
Meanwhile, the city of Los Angeles will enact Red Flag No Parking restrictions at 8 a.m. Thursday. The restrictions, which will remain in place until further notice, prohibit street parking in designated Very High Fire Hazard Severity Zones to ensure roads are clear to ensure access for fire crews trying to respond to a brush fire, and to ensure residents can leave the area if evacuation orders are issued.
Cal Fire announced that it is increasing staffing over the coming days to be prepared for potential wildfires, but the Los Angeles Fire Department did not order red flag parking restrictions on narrow hilly streets.
“With some of the most destructive and deadliest fires occurring October through December, we need Californians to not be complacent,” Cal Fire Chief Thom Porter said. “Wind-driven fires move fast, and residents need to be ready to evacuate at a moment’s notice in the event of a wildfire. We have increased our staffing, but need the public to remain vigilant. It is important to follow evacuation orders and leave early as fires move very fast under these conditions.”