Pacific Gas & Electric began cutting off power to nearly 800,000 customers across large swaths of Northern and Central California on Wednesday morning, in a planned outage that it says is necessary to avoid the risk of fire.
PG&E gave residents in more than 30 counties advance warnings about the power cut, which it says would "proactively" reduce the dangerous effects of a potential "widespread, severe wind event" forecast for Wednesday.
The utility giant's transmission lines have been linked to wildfires that have devastated communities in California. It filed for bankruptcy protection in January, and it has been roundly criticized for mismanagement and safety failures.
As of Wednesday morning, people in Humboldt, Marin, Napa, Sonoma and other counties are without power in the initial phase of PG&E's Public Safety Power Shutoff.
"The decision to turn off power was based on forecasts of dry, hot and windy weather including potential fire risk," PG&E said in a statement about the outage.
"Based on the latest weather forecasts and models, PG&E anticipates that this weather event will last through midday Thursday, with peak winds forecast from Wednesday morning through Thursday morning and reaching 60 to 70 mph at higher elevations."
California is at the peak of its wildfire season. And the risk of strong wind gusts, paired with hot, dry weather raises the risk of trees being knocked into power lines and sparking a fire.
PG&E is taking the aggressive step as it hopes to avoid a devastating fire event like 2018's deadly Camp Fire in Butte County, which claimed the lives of as many as 86 people and torched 14,000 homes and businesses. Another fire in California's wine country in 2017 killed 22 people and destroyed more than 36,000 acres.
Last month, PG&E agreed to pay $11 billion to resolve insurance claims from those two fires, though earlier this year, state fire investigators determined that a private electrical system, not PG&E, was responsible for the wine region blaze.
The power shut-off could last up to five days or more in some areas, according to the San Francisco Chronicle, citing the Napa County Office of Emergency Services. The Chronicle also reports that the outages are expected to "hit parts of all Bay Area counties except San Francisco."
On Wednesday, the National Weather Service warned residents that a red flag warning was in effect for the North and East Bay Hills and Valleys as well as the Santa Cruz Mountains.
The NWS predicted a "very dry airmass will sweep across the region," and minimum humidity values are expected to plummet and remain low.
"The combination of strong and gusty offshore winds, very low humidity, and dry fuels will create critical fire weather conditions today through Thursday," according to the latest alert by the NWS in San Francisco.
PG&E announced Monday that its meteorological and operations teams were monitoring the forecasts and "considering proactively turning off power for safety." By Tuesday evening, it confirmed the shut-off would proceed.
The first phase began just after midnight local time, impacting nearly 513,000 customers, PG&E said. A second shutdown is expected to take place after noon Wednesday that will affect another 234,000 customers in counties including Mariposa, San Joaquin, and Santa Clara.
A potential third shutdown phase is being considered, according to PG&E. That plan could affect an additional 42,000 residents.
PG&E and state officials urged customers to plan ahead for refrigerating food and some medications, to find ways to power phones and other electronic devices, and to restock emergency kit supplies.
As people grapple with how to adapt to life without reliable electricity, the Marin County Sheriff's office tweeted tips on how to open a garage door if it doesn't have an emergency battery.
"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," said Michael Lewis, PG&E's senior vice president of electric operations, in a statement.