REDDING, Calif. – Nearly 2 million Californians could be left in the dark at least through Thursday as the state's largest utility implements a preemptive power shutdown in an aggressive effort to curb wildfire risks amid high winds and hot, dry conditions.

Pacific Gas and Electric spokesman Mark Mesesan said Wednesday that it may take days to restore electricity to some customers because power lines and equipment must be checked before being reenergized. The strong winds, some as high as 70 mph, are expected to abate by Thursday afternoon.

Residents in areas where power was going out lined up at gas stations and streamed into stores in pursuit of generators, flashlights, batteries and nonperishable food. The outage also prompted schools and universities to cancel classes and some businesses to close.

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The first phase of the Public Safety Power Shutoff cut out electric service to 513,000 homes and businesses — or more than 1 million people — starting early Wednesday morning and affected mostly Northern California. Crews had restored power for 50,000 subscribers in the Sierra Foothills by Wednesday evening, PG&E Vice President Sumeet Singh said in a news conference.

The second phase was initially scheduled to start at noon and stretch to parts of cities as large as San Jose and Santa Cruz, impacting about 234,000 subscribers, but the majority of it was delayed. Shutoffs began around 10:30 p.m. and will continue through midnight Pacific time, said spokesperson Jennifer Robison.

PG&E said an additional 4,000 subscribers in the southernmost areas it covers in Kern County could go also dark Thursday, down from an original estimate of 43,000. Every customer account represents between two and three people.

Nearly all nine counties in the San Francisco Bay Area were subject to the shutdowns, the only exception being the city and county of San Francisco.

PG&E released a new website allowing customers to search for outages by zip code and find help centers. Over the next day, customers will be able to find updates on power restoration there, too, said PG&E Senior Vice President Laurie Giammona.

Once dangerous weather conditions in Northern California subside around noon Friday, Singh said crews can begin visually inspecting power lines for damage during daylight hours. Power can be restored quickly if there is no damage, he said, but repairing lines may take longer.

PG&E is trying to prevent downed power lines or vegetation contact with its equipment from sparking fires. Some of California’s most destructive blazes in recent years were started by the utility's power lines.

Parts of Southern California could also lose electricity. Southern California Edison said it was considering implementing the shutoff plan to cut power to 173,000 customers. San Diego Gas Electric said 34,000 of its customers were put on similar alert.

At approximately noon, 65 customers in Kern County on the Tehachapi circuit saw their power cut due to high winds, SCE said. A weather station at the Tehachapi Municipal Airport indicated maximum gusts at 32 mph for the next 24 hours.

"We understand the effects this event will have on our customers and appreciate the public's patience as we do what is necessary to keep our communities safe and reduce the risk of wildfire," PG&E senior VP Michael Lewis said in a web posting.

Some officials expressed frustration with the PG&E plan. Gov. Gavin Newsom said the blackout was necessary but urged the utility to improve infrastructure, a sentiment also expressed by Oakland Mayor Libby Schaaf.

Rep. Doug LaMalfa, a Republican whose district includes Redding, blamed the need for an outage on decades of frivolous lawsuits, bureaucracies, excessive forest protection policy and onerous regulations utilities face.

"Expecting the power to stay on when the wind blows isn’t that giant a leap for mankind," LaMalfa said. "Yet here we are 50 years after the first moon landing having great inconvenience and personal or economic losses for many of our residents."

The precautionary outages had some of those residents grumbling, many about food they fear will go bad.

"We just bought a whole bunch of groceries, and now we have to dump it," said Annie McNally of Jones Valley, California. "I am so fed up with these power outages."

Some had even bigger concerns.

Lisa Round of Anderson said she has sleep apnea and needs to wear a mask to bed, and her mother requires oxygen from a tank at night.

With the likelihood of losing electricity for her mask overnight Tuesday for Wednesday, "I actually plugged it into my car. I ran my car so that I wouldn’t die in my sleep."

The blackout warning system hasn't played well. The company's website has struggled with the heavy traffic, preventing or delaying some subscribers from finding information about the blackouts.

"We understand our customers are frustrated with the website not working. That's something we're working very hard to fix,'' spokesman Jeff Smith said. "We've tried to mitigate that a little by putting the maps and things that are available out on our social media accounts, so that's an alternative for folks. We apologize for the problem.''

The University of California-Berkeley and California State University-East Bay were among colleges forced to close their doors. Schools were shuttered for tens of thousands of elementary and high school students as municipalities braced for days without power.

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Lewis said PG&E anticipates the wind "weather event" will last through midday Thursday; peak winds are forecast to reach 60-70 mph at higher elevations.

PG&E opened resource centers with charging stations and restrooms available to the public during daylight hours.

“They’re places where affected customers can come in to charge electronic devices, obtain bottled water and use available restrooms,” Mesesan said. “It’s more of an in-and-out option. They’re not equipped as a place to stay."

PG&E has been under intense scrutiny since November, when the deadliest and most devastating wildfire in state history roared through Butte County. California fire officials determined the blaze, which killed 85 people and destroyed more than 10,000 homes, was ignited by the company's transmission lines.

The beleaguered utility filed for bankruptcy this year, and a new CEO tried to restructure the company and win back customer confidence.

The state is bracing for another severe wildfire season, although that season has become just about year-round. PG&E ordered a much smaller power cutoff in June involving thousands of customers in the Northern California counties of Napa, Solano and Yolo.

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Tuesday, Cal Fire issued a fire warning across much of the state.

"There is a #RedFlagWarning for most of Northern California and #FireWeatherWatch for the southernmost region of California from Wednesday morning to Thursday evening due to gusty winds and low humidity," Cal Fire warned on Twitter. "This is #CriticalFireWeather and caution should be taken when outdoors."

Bacon reported from McLean, Virginia. Contributing: Kristin Lam and Marco della Cava, USA TODAY; David Benda, Matt Brannon and Alayna Shulman, Redding Record Searchlight; Gabrielle Paluch, Palm Springs Desert Sun