California’s three largest utilities are all considering turning off power in regions where dangerously strong winds are expected to increase the risk of wildfires this week.

More than 350,000 customers from Kern to San Diego counties could lose power due to the planned safety shutdowns. A red flag warning of “particularly dangerous situation”, the highest fire weather warning, is in effect for parts of the region.

Just last month, officials warned of similarly damaging Santa Ana winds and low humidity as the Mountain Fire ignited in Ventura County, leading to one of Southern California’s most devastating wildfires in recent history. The strong winds pushed the fire into surrounding neighborhoods, eventually destroying more than 240 structures, including many homes.

Southern California Edison on Monday is considering planned outages for more than 250,000 customers across much of its service area “due to increased wildfire risk.”

The majority of customers were in Ventura, Los Angeles, San Bernardino and Riverside counties, where more than 40,000 in each county could lose power. About 4,000 SCE customers in Kern County could also lose power.

David Eisenhauer, a spokesman for SCE, said the utility could turn off power any time between Monday and at least Wednesday because wind is expected to remain a concern.

San Diego Gas & Electric is considering shutting off more than 117,000 customers in San Diego and Orange counties. The outages are possible from Monday to Friday at noon, the energy supplier reported.

Pacific Gas & Electric is also considering outages for about 600 of its customers in rural Kern County, according to PG&E spokesman Jeff Smith. The utility said shutoffs would likely occur through at least Wednesday “due to high winds and dry conditions.”

The practice of planned public safety power shutoffs began after it was discovered that downed power lines had sparked some of California’s deadliest and most destructive fires. The preventative strategy is used to prevent electrical infrastructure from starting fires during strong wind events.