Footage from Seabright State Beach in Santa Cruz captures a dramatic ocean rescue as a teenage lifeguard pulls a 10-year-old boy from powerful surf.

The video shows conditions worsening before the California State Parks lifeguard reaches the child and brings him safely back to shore.

The incident happened on 25 July after sudden heavy surf hit the US west coast beach, with waves reaching up to 3 metres high.

The 16-year-old lifeguard was praised for his quick response as he entered the water in dangerous conditions.

The incident highlights the risks posed by rapidly changing conditions along the California coast, where strong surf can develop with little warning.