LOS ANGELES — Thunderstorms spit lightning and unleashed downpours across warm and humid Southern California on Friday, causing widespread power outages and injuring one man.

About 31,000 Southern California Edison customers lost power when storms hit Orange County about 9 a.m., and more outages were expected into the evening as storms continued elsewhere, the utility reported.

Fullerton College canceled classes and closed its 22,000-student campus due to an outage, the school’s website said.

In San Bernardino County, a 50-year-old man was injured by a lightning strike on a crane at a construction site next to a hospital in Fontana. The victim was hospitalized with injuries that were not life-threatening, a Fire Department spokeswoman said.

The area was hit by extensive dry lightning as erratic weather moved through, she said. “It’s best to stay inside if you can.”

Southern California’s thunderstorms were being fueled by subtropical moisture pulled into the region by a low-pressure area to the southwest, the National Weather Service said.

Thunderstorms were possible through Sunday, but some cooling should begin Saturday, forecasters said.

Thousands of San Diego Gas &Electric customers experienced power outages Thursday when similar wild weather swept through, City News Service reported. Lightning also started several small brush fires.