California's biggest utility admitted Friday its electrical equipment may have ignited a ruinous wildfire spreading across the state's wine country despite preventative blackouts, and later warned that up to 2.1 million people in Northern and Central California could lose power in the largest planned power shutoff in the region.
The disclosure from Pacific Gas & Electric came as firefighters simultaneously battled flames in Northern and Southern California: the fire amid Sonoma County's vineyards, and a wind-whipped blaze that destroyed homes near Los Angeles.
The fire near the Northern California town of Geyserville burned at least 49 buildings and 65 square kilometres and prompted evacuation orders for some 2,000 people.
The utility said it has notified about 850,000 customers in 36 counties that it may cut off power between 6 and 10 p.m. Saturday to prevent wildfires. The outages may last until midday Monday.
Forecasters are predicting the strongest winds in years throughout the region.
The shutoff could affect a larger number of people than two weeks ago, when PG&E cut off power to 738,000 customers in 34 counties.
California Office of Emergency Services director Mark Ghillarducci is warning Californians to be prepared with supplies because gas stations and grocery stores might lose power.
PG&E resorted to shut-offs after fallen power lines and other electrical equipment were blamed for several blazes in recent years that killed scores of people, burned thousands of homes and ran up billions of dollars in claims that drove the utility into bankruptcy.
However, PG&E said Thursday it didn't de-energize a 230,000-volt transmission line near Geyserville that malfunctioned minutes before the fire erupted. The company reported finding a "broken jumper" wire on a transmission tower Wednesday night.
PG&E CEO Bill Johnson said it was too soon to know if the faulty equipment started the fire. He said the tower had been inspected four times in the past two years and appeared to have been in "excellent condition."
While the high winds in Northern California had died down by Friday, they were expected to pick up over the weekend, with gusts of 64 to 97 km/h in many places, and PG&E warned it may black out an even larger region.
50,000 under evacuation orders in south
Meanwhile, punishing Santa Ana winds that pushed fires into Los Angeles-area neighbourhoods — burning six homes and forcing tens of thousands to evacuation — were expected to last through the weekend and could prompt more power shutoffs across the state.
As many as 50,000 people were under evacuation orders, while Los Angeles County Fire Chief Daryl Osby said more than 15,000 structures were threatened by a wildfire that has scorched nearly 17 square kilometres and is only five per cent contained.
The threat of hot, dry, winds driving flames far and wide was met with fleets of aircraft and hundreds of firefighters on the ground, who tried to protect homes where backyards were surrounded by trees and brush. In some places, they failed.
As hot embers flew, subdivision homes and rural ranch properties were damaged or destroyed in the Canyon Country area of Santa Clarita and in the nearby community of Castaic.
"We know of at least six but that number may rise," Los Angeles County Supervisor Kathryn Barger said.
Watch fast-moving fires set houses alight in Santa Clarita:
Some residents tried to fight the blaze with garden hoses.
In the rural areas, where at least two ranch houses burned, people rushed to rescue dozens of horses, donkeys, goats, a pig and even an emu.
No injuries were reported but fire officials say a firefighting helicopter was struck by a bird and its windshield damaged, forcing it out of the fight until Friday.
Firefighters were also responding to a new wind-driven wildfire that erupted Friday morning near the community of Ramona, about 48 kilometres northeast of downtown San Diego.
The California Department of Forestry and Fire Protection (Cal Fire) said the blaze has grown to more than 20 hectares, and evacuation orders have been issued for half a dozen roads in the area.
The San Diego County Sheriff's Department said an evacuation centre has been set up at a rodeo ground.