Lightning lit up the night sky as isolated thunderstorms hit the Coachella Valley and surrounding areas on Labor Day.
The series of storms moved into Southern California from neighboring Arizona overnight into Monday, according to the National Weather Service.
There were more than 6,300 in-cloud flashes of lightning through the 5 a.m., and 137 cloud-to-ground strikes, the weather service tweeted.
The wild weather prompted a flash flood warning in areas including Idyllwild, Palm Springs and Indio that expired around 4:30 a.m. Monday.
While the activity subsided before dawn, more thunderstorms are possible in inland mountain and desert areas of Riverside County during the day, forecasters said.
The best chance for additional storms in those areas will be Monday and Tuesday afternoons, according to the weather service.
Forecasters warned the storms could trigger isolated flash flooding.
A flash flood watch is in effect in mountain and desert areas throughout Southern California. The watch is scheduled to expire around 8 p.m.