Californians could find themselves in the dark again this week, this time due to power shut-offs imposed by the state’s largest utility to reduce the risk of more wildfires.

Pacific Gas and Electric shut off the power for more than 170,000 homes and businesses as of Tuesday morning, the utility said. The shut-offs are occurring for customers in 22 counties, and the utility plans to turn off power in at least one more county Tuesday afternoon. It is estimated that the shut-offs could affect more than 500,000 people.