A “life-threatening and destructive” windstorm is forecast to last through Thursday, bringing with it severe fire danger and widespread power outages across Southern California.

This is the third time in as many months that strong Santa Ana winds have prompted Southern California Edison to cut power to its customers.

The map below shows which areas are currently without electricity and which are under consideration for power cuts.

As of Tuesday morning, more than 400,000 people were under consideration for a shutoff.

The map on Edison’s website is updated in near-real time, though a spokesman said significant events could result in some delays. The utility encourages customers to enter their address for more information about their outage, such as the duration of increased fire risk.

Public safety power shutoffs are aimed at mitigating threats, often in areas where its equipment could be at high risk of sparking a wildfire. The utility’s meteorological teams use their own weather models and government data to weigh possible shutoffs. They monitor not only wind speeds and gusts, but the presence of windblown debris and vegetation dryness, using hundreds of weather stations and sensors.

“We always try to turn off power in the most localized way possible,” Jeff Monford, a spokesperson for Southern California Edison, said. “We know that this is not just an inconvenience. We know these outages are actual hardships, and turning off the power really is the measure of last resort.”

While Edison tries to give customers notice of a shutoff three days in advance, that is not always possible, Monford said.

“This is a phenomenon of the increasing effects of climate change on weather. We have more weather extremes that can change more quickly than we might be accustomed to,” he said.

If you see a downed power line, Monford added, assume it is live, stay at least 100 feet away and call 911.