SAN FRANCISCO (AP) — Pacific Gas & Electric has started cutting power to about 25,000 customers in northern and central California as high winds threatened to damage electrical equipment, which could ignite wildfires.

Forecasters issued an extreme fire danger warning as winds gusted to 55 mph in mountains and 25 to 45 mph in valleys. PG&E cut the power Monday and says the planned outages are necessary because winds could raise the risk of trees falling on power lines and sparking fast-spreading wildfires.

Southern California Edison warns it may turn off power to 9,000 customers in parts of Kern, Ventura and northern Los Angeles counties to reduce the threat of wildfires.