The state’s power grid manager announced Tuesday afternoon that rolling outages might be used Tuesday to prevent cascading blackouts amid California’s heatwave.

Rotating outages are a series of controlled outages that affect customers for up to two hours. Rotating outages are designed to relieve stress on the grid to help prevent more widespread power outages, a PG&E spokesman said.

As of 3:30 p.m., no rotating outages were in place, according to PG&E.

“However, out of an abundance of caution, PG&E has given advanced notification to approximately 525,277 customers to prepare for potential rotating outages this evening in case they need to take place,” the utility said.

Both PG&E and the California Independent System Operator are urging residents to conserve energy during today’s Flex Alert until 9 p.m.

Clovis Neighborhoods Go Dark Mid-Afternoon

Heat damage led to an outage in Clovis affecting 4,200 customers at 3:22 p.m., a PG&E spokesman said.

“We had to proactively shut these customers off to prevent equipment failure that would have resulted in larger outages with longer durations. We expect to be able to restore those customers at 6:15 p.m.,” said PG&E spokesman Denny Boyles.

How to See If Your House Will Go Dark

You can follow the state’s electricity supply, current demand, and expected peak demand in real-time at this link.

In addition, PG&E customers can look up their addresses to determine if their household will be affected. Visit www.pge.com/rotatingoutages to check your address.