Northern California is bracing for continued high winds and critical fire danger Monday amid planned blackouts that are set to affect hundreds of thousands of people.
Extreme gusts emerged at high elevations Sunday and overnight into Monday morning. In the fire-prone North Bay hills, gusts from 70 to 89 mph were recorded at multiple locations on and near Mt. Saint Helena late Sunday, according to the National Weather Service’s Bay Area office. NWS Reno said it recorded a gust of 106 mph at the summit of Alpine Meadows in the Lake Tahoe region.
Despite those extraordinary winds, no major wildfire incidents were reported by Cal Fire from Sunday afternoon through 7 a.m. Monday.
A few relatively small fires that ignited in Shasta and Tehama counties a few hours prior to peak wind speeds have been mostly controlled. Southwest of Redding, the Point Fire reached 275 acres before spread halted. Cal Fire said Monday morning it is 90% contained. A 133-acre incident called the Dersch Fire popped up southeast of Redding on Sunday afternoon and is also now 90% contained. A third, the Olinda Fire, burned 5 acres southwest of Anderson and is now fully contained.
High wildfire danger continues, though, as the NWS Bay Area office extended a red flag warning that was set to expire Monday to 5 p.m. Tuesday for the North and East Bay areas. Gusts could continue to hit between 60 mph and 70 mph at peaks in those regions through the end of the warning.
— NWS Reno (@NWSReno) October 26, 2020
— NWS Bay Area (@NWSBayArea) October 26, 2020
Pacific Gas and Electric Co. began shutting off the lights Sunday morning and by 6 p.m., more than 225,000 customers were in the dark.
An estimated total of 361,000 homes and businesses across Northern California are planned to be included in the power outage, a blackout spanning parts of 36 counties that could affect 800,000 people.
Thus far, almost 13,000 customers in Butte County have been plunged into darkness, along with nearly 35,000 in Nevada County, 32,000 in El Dorado County, many in Placerville and Diamond Springs, and 25,000 in Shasta County.
Although PG&E scaled back the size of its public safety power shutoff by about 105,000 customers due to better-than-expected conditions, the forecast promises highly hazardous weather through at least Monday.
Amid a red flag warning for the majority of Northern California set to last through Tuesday, meteorologists at the National Weather Service’s Sacramento office predicted winds that could peak at more than 70 miles per hour in certain areas, plus minimum daytime humidities potentially as low as 4%.
The Sacramento Valley is expected to see wind gusts up to 50 mph, while the mountains and foothills could see gusts of 60 mph. The forecast prompted the NWS to issue a wind advisory Sunday lasting through Monday morning in the Bay Area and parts of the Sierra Nevada. Forecasters warned that the high winds could knock down power lines, posing yet another danger of fire starts.
These winds, according to the weather service, will be the strongest Northern California has seen this season, which may result in PG&E’s largest power outage this year.
The weather service said the incoming wind patterns align with those responsible for many massive and deadly wildfires in recent California history.
“Extreme fire weather conditions are forecast through tomorrow due to strong winds, low humidity values, and dry fuels. The strongest winds will occur today and tonight, before gradually trending downward on Tuesday,” NWS officials wrote in a forecast discussion. “The meteorological synoptic setup is uncomfortably similar to recent past events in northern California such as October 27-28, 2019 (Kincade Fire rapid growth), November 8, 2018 (Camp Fire rapid growth) and October 8-9, 2017 (2017 Wine Country Fires rapid growth).”
During a PG&E news conference Sunday night, forecaster Scott Strenfel said the latter hours of Sunday evening will bring the most intensive winds, although a second round of winds are expected overnight Monday as well.
He said that by 6 p.m., the relative humidity in Redding had reached 5%, and a dry air mass in that area will move south, lowering humidity in the region as it goes.
Meanwhile, wind gusts in the North Bay hills had already hit 55 miles per hour, according to PG&E weather observations.
“The risk of catastrophic fires is extremely high,” Strenfel said.
In addition to the hazardous conditions, the next week or so is not expected to bring any rain, according to Strenfel.