On Wednesday, utility PG&E began cutting electricity to almost 800,000 California homes and businesses -- representing roughly 2.4 million people -- to prevent wildfires as high winds are forecast to whip through the state. The outages will hit 34 counties, including much of the San Francisco Bay area, triggering a scramble by residents to prepare for what may be days without power.
As California's climate warms and dries, the massive blackouts could become a new, annual ordeal. The shut-off warning came two years to the day after wildfires tore through Napa and Sonoma counties, and 11 months after one of PG&E's transmission lines triggered the Camp Fire, which leveled the town of Paradise and killed 86 people.
"We have a grid that was built to manage a set of circumstances that don't exist anymore," said Michael Wara, director of the Climate and Energy Policy Program at Stanford University. "We are having to adapt to new circumstances brought about by climate change."
He estimated PG&E's blackout for two days could have an economic impact of as much as $2.6 billion, using a planning tool developed by Lawrence Berkeley National Laboratory.
The Bay Area shut-offs will affect major cities including Oakland, San Jose and Berkeley, which warned residents especially in hillside neighborhoods to prepare for six days without power. California's transportation agency said it was preparing to close two major tunnels in the region due to the loss of power.
San Francisco, which is less prone to wildfires because of its cool climate and minimal open spaces, will be unaffected. The Silicon Valley campuses of tech giants including Facebook and Alphabet are also expected to be spared.
Meanwhile, Edison International's Southern California Edison utility said it was weighing cutting power to 106,000 homes and businesses, most of them in the mountains east of Los Angeles.