SAN FRANCISCO (AP) — Northern California officials urged residents to leave homes in the hills, secure backyard furniture and other loose items and have an evacuation plan ready ahead of powerful winds that could lead to widespread electricity outages and leave more than 1 million people in the dark.

Pacific Gas & Electric said it could black out customers starting Sunday in 38 counties to prevent the chance of sparking wildfires as bone-dry, windy weather returns to the region. In the San Francisco Bay Area, customers in every county except for San Francisco could see their power shut off.

The safety shutoffs were expected to begin as early as Sunday morning and last into Tuesday, affecting 466,000 homes and businesses, or more than 1 million residents, assuming between two and three people per home or business customer.

The winds that could potentially be the strongest the region has seen in 20 years could topple trees and power lines or other equipment that in recent years have been blamed for igniting massive and deadly blazes in central and Northern California, officials said.

East of San Francisco, the city of Berkeley recommended residents consider leaving the hills before Sunday afternoon, especially if they would have trouble getting out quickly during a fire.

In neighboring Oakland, at least 10 parks will close Sunday and Monday. Cities throughout the region planned to open emergency operations centers and add additional police officers and firefighters to patrol high-risk areas. Officials were also encouraging people to have their cellphones fully charged or if they have a landline, to connect an old-fashioned phone and not one that depends on electricity.

“I would ask all of the people who live in high-impact areas mimic us and plan ahead of time and do the planning with their neighbors, with their families and within their own households so that if they are asked to evacuate they’re ready and not just then starting to figure it out,” Oakland Assistant Fire Chief Robert Lipp said.

While about one-third of the affected customers will be in the Bay Area, cuts are predicted to encompass parts of the Sacramento Valley, the northern and central Sierra Nevada, the Santa Cruz Mountains, the Central Coast and parts of southern Kern County.

Some of the largest fires this year have occurred since August but California's most intense fire weather normally comes in the fall. Eight of the 10 deadliest blazes in state history have occurred in October or November.

In November 2018, a blaze ignited by PG&E equipment destroyed much of the town of Paradise in Butte County and killed 85 people. The projected shutoffs included 19,000 customers in parts of that county. A blaze in the Oakland hills in October 1991 killed 25 people.

The National Weather Service issued red flag warnings for many areas, predicting winds of 35 mph (56 kph) or higher in San Francisco and lower elevations and up to 70 mph (113 kph) in mountains. The concern is that any spark could be blown into flames sweeping through tinder-dry brush and forestland.

It said the conditions could equal those during devastating fires in California’s wine country in 2017 and last year’s Kincade Fire. Fire officials said PG&E transmission lines sparked the Kincade Fire in Sonoma County last October, which destroyed hundreds of homes and caused nearly 100,000 people to flee.

“Given that vegetation is now at or near record dryness levels — much as it was prior to the North Bay firestorm in October 2017 — this is a very concerning forecast,” Daniel Swain, climate scientist with UCLA and the National Center for Atmospheric Research, wrote in a blog post.

The public safety power shutoff would be the fifth this year, including one that began Wednesday and that ended late Friday.

At Silverado Ace Hardware store in Calistoga, people were buying generators, electrical cords, flashlights, batteries, gas cans and other items, said Kathleen Collins, the store's assistant manager.

The Napa County town of 5,000 people has been affected by many of the power outages this year. But in the previous outage, the PG&E brought in temporary generators to provide electricity.

“The generators are are still set up out there, so I’m hoping they’re going to keep our power up,” Collins said.

She said losing power is becoming a common occurrence, and people are having to live without electricity for days at time in a region that has been affected by several wildfires in recent years.

“There’s not much we can do about it," Collins said. "We’ve already been devastated so much by these fires. Being without power seems the only solution right now.”

Southern California, which enjoyed several days of cool temperatures and higher humidity, will see the return of warm, dry Santa Ana winds. A fire weather watch is in effect for much of Los Angeles and Ventura counties from late Sunday through Tuesday. Relative humidity levels will plummet, and winds could top 55 mph in valleys, with gusts of 75 mph possible in mountain areas.

Scientists say climate change has made California much drier, meaning trees and other plants are more flammable.

More 8,600 wildfires have scorched well over 6,400 square miles (16,576 square kilometers) and destroyed about 9,200 buildings in California this year. There have been 31 deaths.

All of the huge fires have been fully or significantly contained, but more than 6,000 firefighters remain committed to 19 blazes, including a dozen major incidents, Cal Fire said.

Many of this year’s devastating fires were started by thousands of dry lightning strikes. But some of the fires remain under investigation for potential electrical causes.

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This story has been corrected to show the utility may, not will, cut power to over 1 million people.