The incident occurred on Malibu Canyon Road around 7:30 a.m.
A large rock came tumbling down the hillside and smashed into the windshield of a white Ford Focus. The rock did not go through the windshield but badly damaged the glass. Those inside the vehicle, who were headed to a wedding, were not injured.
A rock also struck another vehicle along Malibu Canyon. This time, the rock struck the car in the front right side, causing a flat tire and damage to the bumper.
A California Highway Patrol officer cautioned motorists driving through the area to be cautious of debris on the road.