A 20-year-old man died after lightning struck 14 people at a popular Los Angeles beach and a golf course.
Los Angeles County coroner's Lieutenant Larry Dietz said the man was taken from Venice Beach and pronounced dead at hospital.
Nine people went to hospitals, including one who remained in critical condition.
The lightning struck as rare summer thunderstorms swept through Southern California.
Steve Christensen said his friend tried to help when lifeguards began searching for a missing swimmer.
"He went out to the water to find him and walked right into him," Mr Christensen said. "He was face down on the bottom."
Mr Christensen said his friend pulled the man from the water, and lifeguards began trying to resuscitate him before taking him away on a truck.
Stuart Acher said he was struck while playing volleyball on the beach.
"All of a sudden there was a big flash of light and a boom, and it felt like someone punched me in the back of my head," he told KABC-TV.
"It went down my whole side of my right body, and my calves sort of locked up, and I fell over. And I looked up and everybody else was, you know, falling over."
Other fire officials said most of those taken to hospitals were mainly shaken up and were expected to recover.
The Los Angeles County Sheriff's Department said the 14th person was struck on a golf course on Southern California's Catalina Island. The 57-year-old man was reported to be in a stable condition.