SANTA CRUZ — PG&E plans to cut power to nearly 800,000 customers in 34 counties Wednesday as dry conditions and high winds threaten to spark wildfires — a preventive outage that would be the largest in state history.

In Santa Cruz County, up to 37,000 customers could lose power starting early Wednesday morning.

“This is a confirmed Public Safety Power Shutoff event that is going to happen,” said Santa Cruz County spokesman Jason Hoppin. “It will impact 37,000 customers, not people, so it’s more than a third of the county.”

The planned outage marks the first time PG&E has opted to preemptively shut off power to customers on a wide-scale, a decision prompted by what will likely be the strongest winds to hit California this fire season. But even after the winds subside Thursday, power could remain shut down for up to five days as workers inspect lines, according to PG&E.

“Most people will see their power restored long before that, but there will be customers that will be out for an extended period of time, so we want everybody to prepare for that,” Hoppin said. “That means getting bottled water dry goods, charge up your cell phones and your backup chargers. If you have electric cars you need to make alternative plans to for transportation.”

Affected customers received notifications from PG&E via automated calls, texts and emails, according to the utility.

PG&E urged customers to prepare for the power shutoff by updating their contact information pge.com/mywildfirealerts or by calling 1-866-743-6589. However, the utility’s website — where residents were directed for updates — was not working much of Tuesday.

Residents in Santa Cruz, Watsonville, Scotts Valley, Capitola, Aptos, Soquel, Boulder Creek, Ben Lomond, Felton, Davenport, Los Gatos, Mount Hermon, Brookdale, Freedom, La Selva Beach, Corralitos, Saratoga and Bonny Doon may be impacted, according to a list provided by PG&E.

Most residents in the cities of Santa Cruz and Watsonville may not lose power, according to local officials and a “general guideline” map put out by PG&E.

PG&E is opening a Community Resource Center in Aptos starting 8 a.m. Wednesday to provide affected customers with restrooms, bottled water, charging for devices and air-conditioned seating for up to 100 people. The center, which will be open during daylight hours only, is at Twin Lakes Church, 2701 Cabrillo College Drive.

It was unclear whether Dominican Hospital could lose power as part of the outage, but the hospital said in a statement it does not expect any disruptions to service.

“In the event of a public safety power shutoff, Dominican Hospital will run on generator power and we do not anticipate any disruption in hospital operations,” The hospital said Tuesday. “Anyone who needs immediate medical care during the shutoff should not hesitate to come to the emergency room.”

Schools may close

As of Tuesday afternoon, all Santa Cruz County public schools planned to remain open Wednesday, according to county Superintendent of Schools Faris Sabbah.

But Sabbah said parents should closely monitor communications from schools, some of which may be forced to close if the planned outages occur.

In the Santa Cruz City Schools District, Soquel High and Westlake Elementary were expected to lose power, according to Superintendent Kris Munro. Both schools planned to remain open.

Most Soquel High classrooms are lit by natural light, and the district was working to bring in battery-operated lights for dark areas of the campus, according to Munro.

In the Pajaro Valley Unified School District, it was unclear which schools could be impacted late Tuesday afternoon. District spokeswoman Alicia Jimenez said school principles were expected to check on each campus early Wednesday morning and notify parents if a closure is needed.

“If the lights turn on, we would assume that business would go on as usual,” Jimenez said.

San Lorenzo Valley Unified School District Superintendent Laurie Bruton said the district was waiting confirmation from PG&E Tuesday evening before sending updates to parents.

UC Santa Cruz said it did not expect the main campus to be affected in a campus message Tuesday.

Cabrillo College was also not expecting to lose power, according to campus spokeswoman Kristin Fabos. But if the campus does lose power, she said it will close and students will be notified via the campus alert system and website.

Widespread impacts

PG&E said it plans to turn off power in stages, starting with counties in Northern California after midnight Tuesday.

“The safety of our customers and the communities we serve is our most important responsibility, which is why PG&E has decided to turn power off to customers during this widespread, severe wind event,” said Michael Lewis, PG&E’s senior vice president of Electric Operations, in a prepared release. “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.”

Winds can knock down live wires and power poles or drive trees and other vegetation into contact with them — and some of California’s most destructive blazes in recent years were started by PG&E power lines.

But the planned outages will not be limited to fire-prone areas because the utility must turn off entire distribution and transmission lines to much wider areas to minimize the risk of wildfires.

PG&E sought bankruptcy protection in January, saying it could not afford an estimated $30 billion in potential damages from lawsuits stemming from recent wildfire. As part of ongoing bankruptcy litigation, last month the company agreed to pay $11 billion to a group of insurance companies representing claimants from deadly Northern California wildfires in 2017 and 2018.

The Associated Press contributed to this report.

Resource Center

PG&E is opening a community resource center in Santa Cruz County to provide information, water bottles, device charging and air-conditioned seating.

Where: Twin Lakes Church, 2701 Cabrillo College Drive.

When: 8 a.m to 6 p.m., Wednesday to TBD.

This story is developing. Check back for updates.