SAN FRANCISCO– About 13,000 customers in Northern California woke up without electricity Friday after Pacific Gas and Electric turned off power to prevent their equipment from sparking wildfires amid dry weather and strong winds expected to last part of the weekend.
The utility began turning off power to customers in 12 counties Thursday evening, including Alameda, Contra Costa, Napa, Solano and Sonoma in the Bay Area, PG.&said E.
PG&E also shut off power to some customers further north in Colusa, Glenn, Tehama and Shasta counties. In total, about 20,000 customers may temporarily lose power in the coming days, PG says&E said in a statement on Thursday.
Forecasters have issued red flag warnings of fire danger through Saturday from the Central Coast through the San Francisco Bay Area and into northern Shasta County, not far from the Oregon border.
They said a major “diablowind” — infamous in the fall for hot, dry gusts — is expected to blow across Northern California beginning Thursday evening and through Saturday, lowering humidity and increasing the risk of wildfires.
According to the National Weather Service, sustained winds of 35 mph are expected in many areas, with possible gusts of up to 64 mph along mountain peaks.
“This could be the most significant wind event of the year so far,” said meteorologist Brayden Murdock of the agency’s Bay Area office. “We want to warn people to be careful.”
During a diablo wind, common in the fall, the air is so dry that the relative humidity drops, leaving vegetation to dry out and ready to burn. The name – “diablo” is Spanish for “devil” – is informally applied to a hot wind that blows from inland toward the coast near the San Francisco region as high pressure builds over the west.
Targeted power cuts were also possible in Southern California, where another infamous weather phenomenon, the Santa Ana winds, is expected Friday and Saturday.
Santa Anas are dry, warm and gusty northeasterly winds that blow from inland Southern California toward the coast and offshore, moving in the opposite direction of the normal onshore flow that brings moist air from the Pacific Ocean to the region.
The National Weather Service has issued red flag warnings for the valleys and mountains of Los Angeles County, parts of the Inland Empire and the San Bernardino Mountains.
Winds around greater Los Angeles won’t be as strong as in the north, with gusts between 25 and 40 mph (40 and 64 kph) possible in the mountains and foothills, said Mike Wofford, a meteorologist with the state’s office weather service in los angeles.
“I think it will be more moderate,” he said Wednesday. “But the risk of fire is still present.”
But snow is forecast for mountain peaks around Lake Tahoe, where up to 2 inches were forecast Friday morning, according to the National Weather Service in Reno, Nevada. The winds around Lake Tahoe can reach speeds of up to 70 miles per hour.
The agency also issued its first freeze warning of the season Friday along the Sierra’s eastern front, in effect from 2 a.m. to 9 a.m., from south of Carson City north through Reno to Lassen, Sierra and Plumas counties in California, where temperatures could drop below low levels. 20s Fahrenheit (-5 Celsius).
“Frost and freezing conditions can kill crops and other sensitive vegetation and potentially damage unprotected outdoor pipes,” the agency said.