PG&E Corp. has deliberately left customers in the dark for the first time as a precaution to prevent wildfires from breaking out.

Almost 60,000 customers in six counties across the Sierra Nevada foothills and Northern California wine country were blacked out Sunday during a windstorm, according to Melissa Subbotin, a company spokeswoman. Service will likely be restored beginning late Monday and continuing into Tuesday,

PG&E @PGE4Me Update: Public Safety Power Shutoff remains in effect for 17k customers in North Bay and 42k in Sierra Foothills. We continue to monitor the weather and will provide updates to our impacted customers in Napa, Lake, Sonoma, Amador, El Dorado and Calaveras counties.

The utility owner could be on the hook for as much as $17.3 billion in liabilities if its equipment is linked to 2017’s blazes, JPMorgan Chase & Co. estimated in August. Investigators have already said that PG&E violated state laws in 11 of last year’s fires. The company took a $2.5 billion pretax charge in the second quarter that was tied to some of those blazes. The state still hasn’t released its report on the Tubbs fire, the deadliest one last year.

PG&E plans to inspect each affected power line for wind damage before restarting it. Inspection crews were deployed early Monday morning, Subbotin said. The region was buffeted with wind gusts above 50 miles (80 kilometers) per hour Sunday, according to the National Weather Service.

Red-Flag Warnings

Red-flag warnings have been issued across a large part of northern California as dry winds, gusting to as high as 55 mph, are set to sweep across the region through late Monday, the National Weather Service said.

“Any fires that develop will likely spread rapidly,” according to a bulletin.

Sempra Energy’s San Diego Gas & Electric utility has shut down electrical lines during windstorms for years, but PG&E had long resisted taking that step. SDG&E cut electricity to 360 customers Monday morning after warning around 4,000 scattered across San Diego County’s mountainous back country that they could lose power.

Edison International, which owns California’s third investor-owned utility, notified customers in 40 communities across Los Angeles, Orange, San Bernardino and Ventura counties that it might cut electricity as winds increased. But by midday Monday, no customers had been intentionally blacked out, a spokeswoman for Southern California Edison said.

Extreme and critical fire conditions also blanket southern California, according to the U.S. Storm Prediction Center in Norman, Oklahoma. More than 14.7 million people live in areas, including Los Angeles, where dry winds could fan flames and turn grasses, brush and trees into kindling for fuel. Some of the worst conditions could occur near Burbank, Oxnard, Simi Valley and Thousand Oaks, the center said.

Shares of San Francisco-based PG&E shares rose 1.2 percent Monday to $47.84. Edison gained 0.3 percent and Sempra was little changed.