Tuna Canyon and Pacific Coast Highway Debris Flow. CHP was responding to the vehicle into the ocean a mile down the road when they came to a stop due to the massive debris flow across PCH. The mud and rocks flooded the homes that were left standing from the fires on the beach side of pch. Massive rocks and boulders are all over pch and Tuna Canyon Road. A CHP Vehicle drove through and got stuck. Officers assisted in pushing the stuck vehicle and freeing it from the mud.