PG&E Corp. shut off power to nearly 25,000 homes and businesses in Northern California as gusty Diablo winds and plummeting humidity levels raise the risk of wildfires.

California’s largest utility cut service to parts of 16 counties, from the San Francisco Bay Area to the Sierra Nevada mountains Tuesday night, according to a statement posted online. On Wednesday, the outages will likely expand to include customers in another county and extend through Thursday.

PG&E began warning of potential power cuts over the weekend, as forecast winds raised the risk of electric lines tangling with tree limbs or falling into dry grass. The National Weather Service issued a red flag warning for a large swath of Northern California, predicting wind gusts up to 50 miles per hour (80 kilometers per hour) that could feed “extreme fire behavior” in the coming days.

“Despite recent wetting rain, we are expecting a widespread and prolonged offshore wind event which will dry fuels out very quickly,” NWS forecasters warned in an advisory Monday.

PG&E filed for bankruptcy in 2019 after the company’s equipment was blamed for sparking a series of deadly wildfires during wind storms.

In southern California, Edison International’s utility there cut power to a few hundred customers in Los Angeles and Santa Barbara counties, according to its website, and was considering shutoffs for more than 250,000 homes and businesses across the region.