400-pound boulder partially severs boy's arm on California beach: Officials

A 15-year-old boy was walking along a Southern California beach when a 400-pound boulder fell on him, severing his arm, local officials said.

The freak accident happened Wednesday afternoon in Emerald Bay in Laguna Beach, the Orange County Fire Authority said.

The teen was walking on rocks along the water's edge when the boulder toppled him, trapping his leg and severing his right arm above the elbow, below the shoulder, Orange County Fire Authority spokesman Tony Bommarito told ABC News.

Lifeguards were the first to reach him and applied a tourniquet to his arm, Bommarito said.

The Laguna Beach Fire Department then arrived and lifted the boulder, which Bommarito described as about the size of a cooler.

The teen was hospitalized in serious condition, Bommarito said.