SAN FRANCISCO (AP) — The Latest on power outages in California (all times local):

9:55 a.m.

Wildfire-prevention power shutoffs affecting thousands of people in northern and central California could spread to other parts of the state where gusty and dry conditions are expected.

Pacific Gas and Electric shut off power to more than half a million customers Wednesday in Northern California in the biggest planned shut off in the state's history.

Southern California Edison is considering power shutoffs to nearly 174,000 customers in nine counties and San Diego Gas & Electric says it has notified about 30,000 customers in backcountry areas.

Red Flag warnings for critical fire weather are expected to go into effect Thursday because of forecasts calling for Southern California's notoriously gusty Santa Ana winds.

___

9:05 a.m.

Residents in Sonoma in California's wine country are swarming to the few businesses opened in the town's square amid a power outage expected to last for days — a bakery with lines out the door and a bar lit with lanterns.

Pacific Gas and shut off power to more than half a million customers in Northern California in the biggest planned shut off in the state's history. The utility said Wednesday it is trying to prevent its equipment from starting wildfires during hot, windy weather.

At the Basque Boulangerie Cafe, workers used battery-powered lights and kept track of cash-only sales by listing them on a sheet of paper. John Vitale says he was happy to find out the cafe had opened after employees prepared the outage by baking bread and pastries.

Vitale tells KTVU-TV he drove around Sonoma looking for a place to get breakfast and feels fortunate to have found coffee and pastries.

___

7:30 a.m.

The California Transportation Department says two tunnels in the San Francisco Bay Area that depend on electricity to function will remain open during a power outage affecting a large swath of Northern California.

Caltrans crews worked through the night to install generators at the Caldecott Tunnel linking the East Bay to San Francisco and the Tom Lantos Tunnel on State Route 1 in Pacifica.

The agency says the generators should be working by midday Wednesday when Pacific Gas and Electric is expected to shut off power in the Bay Area.

The utility began cutting out power to hundreds of thousands of people just after midnight Wednesday to prevent what the utility called an unprecedented wildfire danger.

___

6:30 a.m.

Pacific Gas and Electric has shut off power to more than half a million customers in Northern California in the biggest planned shut off in the state's history.

The utility said Wednesday it will gradually turn off electricity to nearly 800,000 customers to prevent its equipment from starting wildfires during hot, windy weather.

It says a second group of about 234,000 customers will lose power starting at noon.

The utility says it's considering turning off power to another 42,000 customers in areas it serves near Southern California. It says it will determine a time and the specific locations later Wednesday.

___

12:00 a.m.

Millions of people in northern and central California are facing days without power as Pacific Gas & Electric creates the largest preventive blackout in state history.

The utility says it will start to shut down power at midnight Wednesday to customers to reduce the chance of fierce winds knocking trees into power lines or downing equipment and sparking wildfires.

People preparing for the outages emptied shelves of bottled water and batteries, and there were lines at gas pumps.

PG&E planned to shut off power to 800,000 home and businesses in 34 counties through Thursday. But the utility warned it could take up to five days to restore power because the lines must be inspected to make sure they're safe.

To the south, Southern California Edison said more than 106,000 of its customers in parts of eight counties could face power cuts as early as Thursday as Santa Ana winds loomed.