Swaths of Southern California face an increased fire risk Tuesday because of a combination of Santa Ana winds, high temperatures and low relative humidity, with Southern California Edison saying it could shut off power to thousands.
On Sunday, Southern California Edison began notifying customers in Los Angeles, Santa Barbara, San Bernardino and Riverside counties that their power may be shut off starting Tuesday. About 89,500 customers — most of them in San Bernardino and Riverside counties — could be affected, according to the utility.
The mountains and valleys of Los Angeles and Ventura counties could see wind gusts between 25 and 40 mph, the National Weather Service said. The windy conditions are expected to persist through Wednesday morning and are also forecast along the south coast and mountains of Santa Barbara County, as well as the Central Coast.
The National Weather Service has issued a heat advisory for the valleys, the Santa Monica Mountains and the Central Coast. The advisory is in effect Tuesday from 10 a.m. until 8 p.m.
Temperatures are expected to be warmest in the western San Gabriel Valley, where they’re forecast to rise above 100 degrees, the NWS said.
Heating up across LA/Ventura Counties today due to Santa Ana winds. This 24 hour temperature change map shows how the winds impact some areas more than others. Note much of the coastal plain is cooler while the valleys and foothills are 10-20 degrees warmer. #CAwx #LAHeat pic.twitter.com/rSAqzZobqD— NWS Los Angeles (@NWSLosAngeles) September 24, 2019
“When we have easterly winds in general that tends to bring us warmer temperatures because we have cooler ocean water,” said Lisa Phillips, a meteorologist with the NWS in Oxnard. The air also warms up as it blows from higher elevations down toward lower elevations, she said. “That’s where our drier air comes from, as well, so we’re looking at warm, dry conditions across the area,” she said.
The conditions could foster the rapid spread of fire, but the weather service has not issued a red flag warning for Southern California. That’s in part because the weather is expected to last only briefly. Temperatures are forecast to be a bit lower on Wednesday before cooling off significantly later in the week, Phillips said.
Red flag warnings remain in effect for much of Northern California, including the Sacramento Valley, the Sierra foothills and parts of the Bay Area.
Red Flag Warning in effect through Wednesday.— NWS Sacramento (@NWSSacramento) September 24, 2019
A Red Flag Warning means that critical fire weather conditions are either occurring now, or will shortly. Strong winds that are warm and dry can contribute to extreme fire behavior. Practice fire safety #CAwx #OneLessSpark pic.twitter.com/EzuB3NHFuj
California is entering the height of fire season, with a dangerous mix of strong winds and temperatures approaching triple digits forecast across its valleys and foothills.
For the first time this year, several Northern and Southern California communities simultaneously are facing preemptive blackouts to reduce the fire risks.
Pacific Gas & Electric cut power to about 24,000 customers in Butte, Nevada and Yuba counties on Monday night. Crews began re-energizing power lines Tuesday morning after conducting safety inspections, and power was expected to be restored to “essentially all customers” by 6 p.m., the utility said in a news release. PG&E was weighing whether to conduct a second round of shutoffs in the same area Tuesday night into Wednesday morning.
PG&E decided not to proceed with Monday evening shutoffs in Lake, Napa and Sonoma counties in the North Bay, and in El Dorado, Placer and Sutter counties in the Sierra foothills. The utility said it might shut off power to parts of those counties Tuesday, depending on the weather.