Updated at 7:30 p.m. ET
Utility giant Pacific Gas & Electric warned Friday that it is preparing to cut power from Saturday evening through noon Monday to 850,000 customers in Northern California in response to forecasts of historically high winds in the region.
Each customer/household is estimated to represent three people, meaning the planned power outages could leave more than 2.5 million people in the dark.
The potential Public Safety Power Shutoff "may impact 36 counties across portions of Humboldt, the Sierra foothills, Western Sacramento Valley, North Bay, and across the greater (San Francisco) Bay Area, Monterey Bay and northern Central Coast on Saturday, Oct. 26," read a statement by PG&E.
Kern County, the utility's southernmost region, could see power cut on Sunday, the utility's statement added.
California Gov. Gavin Newsom has declared a state of emergency in Sonoma and Los Angeles counties due to two large wildfires. The Kincade Fire in the Bay Area has burned nearly 22,000 acres since it started Wednesday night; the Tick Fire has burned 4,300 acres northwest of Los Angeles.
Both fires were only 5 percent contained as of Friday morning local time, according to the California Department of Forestry and Fire Protection.
The Kincade Fire isn't expected to be fully contained until next Thursday. It has already caused the Air Quality Index in San Francisco to shift from "good" to "moderate." The National Weather Service is warning other Bay Area cities that air quality will continue to drop as smoke continues to move south.
The fire has been aided by dry conditions and gusty winds — and firefighters say the narrow roads and steep terrain of northern Sonoma County have impeded their efforts to combat the blaze.
Winds are expected to pick up Saturday into Sunday, ranging from 45 to 60 mph to peak gusts of 60 to 70 mph at higher elevations.
"Winds of this magnitude pose a higher risk of damage and sparks on the electric system and rapid wildfire spread," read PG&E's statement. "The fire risk is even higher because vegetation on the ground has been dried out by recent wind events."
The power utility told regulators that part of a transmission tower broke near the area of the Kincade Fire shortly before it began. The company shut down power to distribution lines in the area because of potential fire danger posed by those lines. PG&E says weather predictions didn't reach the level that would have triggered a shutdown of the transmission lines.
In a press conference on Friday, Newsom promised affected residents that PG&E will be held accountable for "years and years of greed," although it is not clear whether PG&E's lines were responsible for the Kincade Fire.
"That greed has precipitated in a lack of intentionality and focus on hardening their grid, undergrounding their transmissions lines, they simply did not do their job," Newsom said.
An investigation into the origin of the 2018 Camp Fire, California's deadliest wildfire, found PG&E's electrical lines responsible.
The town of Geyserville in Sonoma County has been evacuated. Cal Fire said that 49 structures have been destroyed and that over 700 more are threatened by the flames. Nearly 1,300 people have been assigned to fight the fire.
Newsom announced Thursday that the state had received a grant from the federal government to assist fighting the flames.
"We are grateful for the swift approval of our request to ensure all resources are available to support the heroic work of our firefighters and first responders working to contain this fire and keep local communities safe," Newsom said.
In the south, firefighters in Los Angeles County continue to fight the Tick Fire, which grew overnight to cover about 4,300 acres. High winds allowed the wildfire to jump a freeway and continue its spread.
Roughly 40,000 residents in the area are under evacuation order. Authorities say 10,000 structures are threatened by the fire.
Cal Fire did not specify when they could control the flames, but the Los Angeles County Fire Department said Friday's weather allowed firefighters to gain headway.
"This morning we have a significant amount of aircraft and retardant reinforcing the containment lines on both flanks," said department Operations Section Chief Mike Inman. "We're confident with the current weather that we can put a dent in this."
The two fires are the latest in California's 2019 fire season, which has resulted in over 185,000 acres of land burned and one loss of life.
Fire and safety officials have issued a red flag warning "throughout California" on Friday, citing gusting winds and very low humidity.
NPR's Colin Dwyer contributed to this report. Paolo Zialcita is an intern on NPR's News Desk.