Los Angeles (AFP) - Rolling blackouts affecting up to 800,000 customers began Wednesday in parts of California as a utility company switched off power because of hot, windy weather that raises the risk of wildfires.
Pacific Gas & Electric, which announced the three-phase deliberate power outage, is working to prevent a repeat of a catastrophe last November in which power lines it owned were determined to have sparked California's deadliest wildfire ever.
In that inferno, 85 people died and a town called Paradise was virtually destroyed. The company has been found responsible for dozens of other wildfires in recent years, too.
This is peak wildfire season in California.
PG&E said the severe weather incident prompting the precautions this time -- hot, dry conditions and winds gusting at up to 70 mph (110 kph) -- is expected to last through mid-day Thursday in parts of northern and central California.
The outages could last up to a week in some places. Some 800,000 customers actually means millions of people will be affected.
The city of San Francisco is not affected by the intentional shutoff but much of the surrounding Bay Area could go dark including parts of Silicon Valley.
The first part of the so-called Public Safety Power Shutoff began at midnight Tuesday into Wednesday in northern California in a broad swath of land that includes the Napa Valley wine country. It will affect around 513,000 customers there, the utility company said.
The rest of the San Francisco Bay area was to start losing power in waves around noon local time. A possible third third phase could take place later in the day farther south.
Schools and universities cancelled classes for Wednesday and people stocked up on gasoline, water, batteries and other basics, news reports said.
PG&E said it expected to start turning the power back on on Thursday but can only do this after inspecting its equipment for damage and this could take days in some areas.