Surfers have been hitting the big waves at Half Moon Bay in northern California on Friday, in what is often described as one of the world's "most hazardous" sporting competitions.

Some waves were forecast to peak at between 12 and 14 feet (3.7m to 4.3m), producing wave faces of up to 30 feet.

The Titans of Mavericks contest is not for the faint-hearted, with surfers allowed to compete by invitation only.