SAN FRANCISCO (CBS SF) — A burst of gusty winds forecast to begin Sunday will be carrying the same wildfire threat as the weather conditions that helped spark the deadly 2017 Wine County October firestorm that included the devastating Tubbs Fire, the National Weather Service warned.
The approaching conditions were threatening enough that Berkeley officials took to Twitter to tell hills residents to get ready to evacuate.
“While we have had many Red Flag Warnings this year, this event poses a greater threat. Hills residents should consider leaving before Sunday afternoon,” the officials tweeted.
A Red Flag Fire Warning was set to go into effect for most of the San Francisco Bay Area at 8 p.m. Sunday and extend all the way to 11 a.m. Monday. Pacific Gas & Electric was already predicting that more than 1 million customers — 466,000 homes and businesses — across Northern California will have their power turned off as a precaution.
Cuts are predicted to encompass parts of the Sacramento Valley, the northern and central Sierra Nevada, upper elevations of the San Francisco Bay Area, the Santa Cruz Mountains, the Central Coast and portions of southern Kern County.
Forecasts call for the “the driest humidity levels and the strongest winds of the wildfire season thus far,” a PG&E statement said.
“Expect the first burst of winds to spread over the North Bay Sunday afternoon as winds come down the Sac Valley and spread over the Bay Area,” the National Weather Service warned. “Expect increasing winds during the late afternoon/evening hours before dark. Then as the sun goes down Sunday night a strong burst of winds will rapidly pass over the Bay Area.”
“Of course the strongest wind potential will be in the hills but there is fairly high confidence that winds will mix down into the lower elevations and then crash along the coastline from Bodega Bay to Half Moon Bay before spreading offshore.”
Northern winds would whip through the area at 20 to 30 mph with gusts up to 50 mph and humidity levels will plunge to as low as 5 percent. According to the U.S. Drought Monitor, the vast majority of Bay Area communities are in an area of severe or extreme drought conditions.
Meanwhile, the weather service said San Francisco has received just 0.06 of rain since May 18th — a span of 158 days. And there are no showers forecast for the rest of the month.
The drought conditions, tinder-dry hills, low humidity and gusty winds are a formula for a wildfire outbreak.
“In simple terms this event looks to be on par with the 2017 wine country fires and last years Kincade fire (that occurred Oct 26-27th 2019),” the weather service warned. “The 2017 wine country and 2019 Kincade peaked between 9 p.m. and roughly 1-3 a.m. at night. This event may arrive slightly earlier but should any fires start it will be a long night of gusty winds.”
“The airmass appears to be much drier with humidity values forecast to plummet into the single digits and teens,” the weather service added. “There will be no marine layer so even the valleys will be bone dry. And as has been noted throughout the week this will all occur on top of record dry fuels. So yes it has similarities to the 2018 Camp Fire as well.”
The winds will not only be carrying a wildfire threat, they also will likely topple trees and rip off branches throughout the San Francisco Bay Area.
“A High Wind Watch covers the entire Bay Area, not just the hills,” the weather service said. “Wind damage will be likely for any fire weakened trees. Downed trees, branches and powerlines will be a high possibility… As noted for comparison this will be on par with the 2017 wine country and 2019 Kincade fire. Still the setup is slightly different and will favor strong wind potential over a larger region that will include all of the East Bay, SF Peninsula and much of the Santa Cruz Mountains as well as Highway 1 corridor from Sonoma southward to Half Moon Bay.”