California’s largest utility has begun widespread blackouts affecting nearly half a million people as dangerous fire weather returned to the state.

The Pacific Gas & Electric Company said on Wednesday the shutoffs would begin around 2pm in the Sierra foothills, followed soon after by blackouts north of the San Francisco Bay Area. In all, the power will be cut to portions of 17 counties. The outages will last about 48 hours, the utility said.

The Santa Rosa fire department tweeted that shutoffs had started in the city and it was getting multiple reports of outages.

Meanwhile, Southern California Edison said it could cut power on Thursday to more than 308,000 customers in seven counties and San Diego Gas & Electric is warning of power shutoffs to about 24,000 customers.

The utilities said they were concerned that winds forecast to top 60mph (97km/h) could throw branches and debris into power lines or topple them, sparking wildfires.

PG&E cut power to more than 2 million people across California in rolling blackouts earlier this month, the largest deliberate blackout to prevent wildfires in state history. The shutoffs caused schools to close and many businesses to shutter. Residents complained PG&E communicated late and ineffectively, even failing to keep its website running smoothly during the outages.

The utility – the largest in the United States - declared bankruptcy in January, in part because of potential liabilities from its role in some of the 2017 northern California fires and the 2018 Camp fire.

Experts and authorities are warning that shutoffs may be the new normal in the state amid a deepening climate crisis. “There were bad fires in the 20th century, but more or less, there was a power system that worked,” Michael Wara, the director of the Climate and Energy Policy program at Stanford University, told the Guardian last month. “I think what’s different is the weather extremes are much more extreme and that’s a predictable effect of climate change.”

“I think it’s not panic per se, just, ‘Eh, we gotta do this again?’” said Kim Schefer, the manager of Village True Value Hardware in Santa Rosa.

Schefer directed customers to gas cans and batteries as they prepared for what many see as a costly, frustrating new routine.

The California governor, Gavin Newsom, sent a sharply worded letter on Tuesday to Bill Johnson, PG&E CEO, blaming the unprecedented mass outage earlier this month on the company’s failure to maintain and upgrade its equipment. State rules leave utilities to control when they will shut down the power, and how they will choose to do it.

PG&E says the shutdowns are not about money.

The only goal “is to prevent a catastrophic wildfire”, Johnson said in a Tuesday briefing.