About 90,000 people are under evacuation orders near Sonoma County in Northern California as severe winds are expected to cause the Kincade Fire to spread rapidly Saturday night. "You cannot fight this," said Sonoma County Sheriff Mark Essick.

It is "truly a selfish act to stay at home and try to fight this," Essick said.

The Sonoma County sheriff announced earlier Saturday that the towns of Healdsburg, Windsor and their unincorporated areas would be evacuated by 4 p.m. as flames from the expanding Kincade Fire driven by "Diablo winds" continued to advance.

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Wind gusts of up to 80 mph — near hurricane-force wings — could be expected in some areas, said CBS News climate and weather contributor Jeff Berardelli said. "That means very rapid, changing conditions," Berardelli said.

Pacific Gas & Electric, California's largest utility, began shutting off power at 5 p.m. PT, the third power shutoff in as many weeks. PG&E said the blackouts would affect 940,000 homes and businesses in 36 counties for 48 hours or longer throughout the San Francisco Bay Area, wine country and Sierra foothills. That's about 90,000 more customers affected than previously predicted.

So far, the Kincade fire has scorched almost 26,000 acres, destroyed 77 structures, including 31 homes, and was only 10% contained as of 7 p.m. on Saturday, CBS San Francisco reported.

"The winds are expected anywhere between 8 p.m. and midnight and from all reports they're expected to be extremely strong," said Brian Vitorelo with the California Department of Forestry and Fire Protection.

The Sonoma County Sheriff's office extended the evacuation zone all the way to the coast Saturday evening. Earlier, the Sheriff's office added the new warning area to two other potential evacuation zones — the Dry Creek Valley west to Forestville and Larkfield and Mark West Drainage.

Traffic on southbound 101 heading away from the evacuation was slow and bumper-to-bumper as thousands traveled toward a safe haven from the blaze.

A blaze Thursday destroyed at least six homes in the Santa Clarita area near Los Angeles and led to evacuation orders for up to 50,000 residents, although some were allowed back home Friday night after Santa Ana winds began to ease.

To the north, firefighters raced to make progress against a blaze near Geyserville in Sonoma County before ferocious "diablo winds" returned. The fire had burned 49 buildings, including 21 homes, and swept through nearly 40 square miles of the wine-growing region. It was 10% contained by Saturday morning.

One firefighter was injured protecting two trapped residents from the flames, CBS San Francisco reported. All three were taken to a local hospital suffering from non-life threatening injuries and "were expected to survive."

No cause has been determined for any of the current fires, but PG&E said a 230,000-volt transmission line near Geyserville had malfunctioned minutes before that fire erupted Wednesday night.

Structures burn at a vineyard during the Kincade fire near Geyserville, California on October 24, 2019 https://www.bbc.com/news/world-middle-east-48104463

The utility acknowledged that the discovery of the tower malfunction had prompted a change in its strategy.

"We have revisited and adjusted some of our standards and protocols in determining when we will de-energize high-voltage transmission lines," Andrew Vesey, CEO of Pacific Gas & Electric Co., said at a briefing Friday.

The weekend forecasts detail what could be the strongest winds of the year coupled with bone-dry humidity.

"These places we all love have effectively become tinderboxes," Vesey said. "Any spark, from any source, can lead to catastrophic results. We do not want to become one of those sources."

The possible link between the wine country fire and a PG&E transmission line contained grim parallels to a catastrophic fire last year that tore through the town of Paradise, killing 85 people and destroying thousands of homes in the deadliest U.S. fire in a century.

State officials concluded that fire was sparked by a PG&E transmission line.

Asherah Davidown, 17, of Magalia and her family lost their house, two dogs and a car in the Paradise fire. She said her family was preparing for another power outage by filling the gas tank of their car and buying non-perishable foods and batteries for their flashlights.

The outages reminded her of her family's vulnerable position as they struggle to get back on their feet.

"My house doesn't have a generator so that means another weekend of sitting in the dark with no Wi-Fi, no food in the fridge and shopping in increments since we don't know how long the power may be out," Davidown said.

The continuing round of power outages made her feel somewhat vulnerable as her family tries to get back on its feet, she said.

"For the most part a lot of people feel really helpless. Their livelihoods are at the fingertips of a corporation," she said. "There's still a lot of hurt and emotional recovery. Having our basic needs repeatedly taken away is really unfortunate."