PG&E shut down power for about 500,000 customers in Northern California early Wednesday, but was able to restore it for about 44,000 during the day, the company said at a press conference. An additional 250,000 customers may lose power later Wednesday, the utility said.
"We took this step to ensure safety as a last resort, and we are committed to reducing the risk of catastrophic wildfire events" Sumeet Singh, vice president of PG&E's Community Wildfire Safety Program, said Wednesday.
Diablo winds sweeping across arid Northern California "historically are the events that cause the most destructive wildfires in California history," said PG&E meteorologist Scott Strenfel.
The wind is expected to subside Friday, Strenfel said. PG&E crews will then examine their system for damage and begin to restore power for customers. That could take several days after the wind dies down, Singh said.
"We very much understand the inconvenience and difficulties such a power outage would cause and we do not take or make this decision lightly," he said. "This decision ... was really focused on ensuring that we're continuing to maintain the safety of our customers and our communities."
The utility said it expects to restore service to as many as 80,000 more customers Wednesday evening if it can be done safely.
Firefighters were working to put out a grass fire at a wind turbine farm in Solano County Wednesday. Customers in that county were affected by the shutdown.
The plan, critics say, lets PG&E get away with inconveniencing its customers and costing businesses instead of upgrading its infrastructure to prevent fires.
"I'm angry at PG&E," Blair Roman, a PG&E customer who's out of power in Mill Valley. "Most of my friends are angry as well."
"They didn't do what they were supposed to do and keep up with the lines and the power," Roman said. "Their answer to everything is to just shut it off so we can't get blamed for it. It's a major inconvenience, it's going to cost companies billions of dollars. And it all could have been avoided."
"This has to change," Nielsen said in a release. "PG&E's decision to protect itself from liability at the expense of hardworking Californians will not be tolerated. This disregards people's livelihoods. We depend on electricity to live and earn a living."
San Jose officials also said they would prefer that PG&E improve its equipment instead of imposing outages.
"We really want to put pressure on PG&E to make investments on their infrastructure to make it safe and reliable so they won't have to shut down when there are weather events," said deputy city manager Kip Harkness. "And we're talking to them and making that stance known to them," he said.
Not all of the customers -- about 2.5 million people, by Nielsen's estimate -- live in an area where there's a higher risk of fires at the moment.
"(That's) because of the interconnected nature of our electrical grid and the power lines working together to provide electricity to cities, counties and regions," Singh said.
"Most people don't realize what an outage really means," one of those hotel guests, Marilyn Varnado of eastern Oakland, told KGO. "Stop lights are not going to be working. There's going to be a lot of crazy things going on, and I just think there's going to be some tragedies because of that."
By Wednesday, there were long lines for gas and empty store shelves already in some parts.
Several school districts and a major university have canceled classes. And officials in cities such as San Jose are urging people reliant on medical devices to get them charged at certain community centers that will remain powered.
In San Jose, officials are warning of consequences both inconvenient and potentially life-threatening.
Southern and eastern parts of San Jose are expected to see their power cut. Although PG&E says only 38,000 San Jose accounts will be affected, that could translate to as many as 200,000 of the city's 1 million residents, Harkness said.
Because some traffic lights will be out, people should consider driving as little as possible, Harkness said during a Wednesday news conference.
Police, fire, water, sewer and garbage-pickup services will continue, Harkness said. But he urged people to check on vulnerable people, like the sick, elderly and those who rely on medical devices.
"Prepare yourself, prepare your family, and help your neighbors," he said.
A third stage has been significantly reduced, PG&E said Wednesday, and may affect about 4,600 in Kern County. Yesterday, the utility said it could impact 46,000 customers.
The California Department of Transportation has been working with the utility company to secure backup power generators to keep some traffic tunnels open, including the Caldecott Tunnel in Contra Costa and Alameda counties and the Tom Lantos Tunnel in Pacifica, spokesman Bart Ney told CNN.
The Bay Area Rapid Transit (BART) system isn't expected to shut down, its officials said in a tweet. BART has portable generators at certain stations and will have personnel monitoring the generators, a Twitter thread said.
State agencies are working with local governments "to address all emergency management, evacuation and mutual aid needs," the Governor's Office of Emergency Services said.
The National Weather Service has warned of strong winds and low humidity running over dry vegetation, which the service said act as "fuels."
"This is a recipe for explosive fire growth, if a fire starts," the weather service said. "Have your go pack ready."
High temperatures Wednesday are expected to vary widely in the region, from the high 60s in some parts of the Bay Area to the lower 80s elsewhere.
CNN's Stella Chan, Carma Hassan, Joe Sutton and Lucy Kafanov contributed to this report.