HALF MOON BAY -- Three people attending the Mavericks Surf Contest in Half Moon Bay Tuesday were injured when they were struck by rocks falling from a cliff, according to a Half Moon Bay fire spokesman.

Division Chief Clayton Jolley said the fire department received word of the incident around 1:30 p.m.

The victims were a 59-year-old man, a 39-year-old woman and her 9-year-old son, Jolley said.

"They were watching the contest and some rocks let go from up on the cliff," he said.

The woman was airlifted to Stanford Hospital with serious injuries, according to Jolley, who said her son, who was in "pretty good shape" was taken to the same hospital by ground ambulance.

The 59-year-old man, who was apparently not attending the event with the woman and child, suffered a small cut to his forehead and was not hospitalized, Jolley said.

Jolley described the size of the rocks that fell as "pretty substantial."

The surf contest drew about 60,000 spectators, who watched the surfers ride waves as high as 35 feet, according to event organizers.