By JANIE HAR
SAN FRANCISCO (AP) — Pacific Gas & Electric Co. began shutting off electricity Wednesday to 375,000 people in Northern and central California to prevent power lines from sparking wildfires as the region faced a new bout of windy and warm weather.
Some people in the wine country counties of Napa and Sonoma north of San Francisco lost power at about 7 a.m. Power was also cut farther north in portions of Mendocino, Lake and Yolo counties, said Katie Allen, a PG&E spokeswoman.
Nearly 170,000 initially lost electricity, but the shut-offs that started Wednesday morning were expected to affect more people as the outages spread to 18 counties and last into Thursday.
A virtually rainless fall has left brush bone-dry and forecasts called for low humidity and winds gusting at times to 55 mph (89 kph), which might fling tree branches or other debris into power lines, causing sparks that could set catastrophic fires in the region, PG&E officials said.
One Napa County reporting station hasn't seen a measurable drop of rain since mid-September — the first time that's happened since 1905, said Scott Strenfel, PG&E's principal meteorologist.
The northern Sierra Nevada has seen a fraction of an inch of rain in the past two months instead of the usual 5 inches (13 centimeters), he said.
"This lack of rain is keeping the threat of fire very real, this late in the season, in many areas," said Scott Strenfel, PG&E's principal meteorologist.
The dry weather in Northern California came as wintry weather brings rain, wind and snow to Southern California. A storm system dumped about 2 inches (6 centimeters) of rain in the San Diego County area on Tuesday and more was expected Wednesday.
Wet conditions made for a slippery Wednesday morning commute in Los Angeles while heavy flooding stranded drivers in desert areas to the east. Flash flood watches were in effect for some communities east of Los Angeles, with storm warnings up for mountain communities.
Voluntary evacuation warnings were issued for a few communities in an area of Orange and Riverside counties that was burned in a wildfire last year.
In the north, warnings of extreme fire danger covered a large area.
California's state fire agency placed fire engines and crews in position in some counties and had crews ready to staff aircraft and bulldozers.
The weather should ease by Thursday morning, allowing PG&E to begin restoring power, said Mark Quinlan, PG&E's senior director of emergency preparedness and response.
The state's largest utility decreased the number of people who could be affected from an original estimate of about 660,000 based on updated forecasts and some juggling of its power system. The utility said it will closely monitor the weather and could further reduce that number if it improves.
The blackout is the latest in a series of massive outages by the country's largest utility, including one last month that affected nearly 2.5 million people and outraged local officials and customers who accused the utility of overkill and using blackouts as a crutch because it failed to harden its equipment to withstand fire weather.
The outages have been "terribly disruptive" and PG&E is taking steps to avoid them in the future but at the moment, "we won't roll the dice on public safety," company CEO Andy Vesey said.
Meanwhile, California's utilities regulators are demanding answers from wireless providers whose equipment failed during the power outages, leaving hundreds of thousands of people without a way to get emergency alerts or make 911 calls.
The California Public Utilities Commission holds a public hearing Wednesday with executives from AT&T, Comcast/Xfinity, T-Mobile and others.
In a letter calling for the meeting, commission President Marybel Batjer said that "lack of service is not a mere inconvenience— it endangers lives." She said residents do not have the luxury of failed internet or cellphone connections during a wildfire or other disaster.
PG&E initiated four rounds of planned outages in October.
More than 450,000 people were left without communications, according to a group representing rural counties in California. About half of Marin County's cell sites were out of service.
Consumer advocates are urging the utilities commission to establish backup power requirements and make the companies provide detailed information about the location of outages.
The California Governor's Office of Emergency Services said in an Oct. 26 letter to communications companies that their level of engagement was "unacceptable" at a time when redundant infrastructure is necessary.
In written responses made available in advance of Wednesday's meetings, the companies said they did communicate with authorities but that the outages were unprecedented in scope.
The companies said they are improving backup power sources but added that doing so might not be possible in some locations and that generators are not always safe.
Comcast said that its network "like any modern network, fundamentally relies on commercial power to operate."
The utilities commission is frustrated with both communications and utilities companies, saying they failed to share detailed information in real time.
Businesses and residents also have complained of poor communications and say that the outages were overly broad and carried out thoughtlessly.
Associated Press writer Olga R. Rodriguez in San Francisco contributed to this story.