Approximately 13,000 customers in Northern California woke up without electricity on Friday as Pacific Gas and Electric (PG&E) initiated power shutoffs to mitigate the risk of wildfires amidst dry weather conditions and strong winds expected to persist through the weekend. The utility company began cutting power on Thursday evening to customers in 12 counties, including Alameda, Contra Costa, Napa, Solano, and Sonoma in the Bay Area.
PG&E also implemented power shutoffs in Colusa, Glenn, Tehama, and Shasta counties further north. A total of around 20,000 customers may experience temporary power loss in the coming days, according to a statement released by PG&E on Thursday.
Weather forecasters have issued red flag warnings for fire danger until Saturday across the central coast, San Francisco Bay Area, and northern Shasta County near the Oregon border. A significant 'diablo wind,' characterized by hot, dry gusts typical in autumn, is anticipated to sweep through Northern California from Thursday evening to Saturday, leading to decreased humidity levels and an increased wildfire risk.
Sustained winds of up to 35 mph are expected in various areas, with potential gusts exceeding 65 mph along mountaintops, as per the National Weather Service. Meteorologist Brayden Murdock from the Bay Area office of the service highlighted the potential severity of this wind event, urging caution among residents.
During a diablo wind event, the extremely dry air causes a rapid drop in relative humidity levels, desiccating vegetation and elevating fire susceptibility. The term 'diablo' originates from Spanish, meaning 'devil,' and is colloquially used to describe the hot wind blowing from the interior towards the coast near San Francisco as high pressure builds over the West.
In Southern California, targeted power shutoffs are also being considered due to the expected Santa Ana winds on Friday and Saturday. Santa Anas are dry, warm, and gusty northeast winds that blow from the Southern California interior towards the coast, contrary to the usual onshore flow carrying moist air from the Pacific.
The National Weather Service has issued red flag warnings for Los Angeles County valleys and mountains, parts of the Inland Empire, and the San Bernardino Mountains. While the winds in the greater Los Angeles area are projected to be less intense than in the north, gusts ranging from 25 to 40 mph are possible in the mountains and foothills, posing a fire risk.
Conversely, snowfall is expected in the Lake Tahoe region, with up to 2 inches forecasted by Friday morning. Wind gusts around Lake Tahoe could reach 70 mph. Additionally, the service has issued a freeze warning along the Sierra's eastern front, with temperatures potentially dropping into the low 20s Fahrenheit, threatening crops, sensitive vegetation, and outdoor plumbing.
