It happened around 4:30 Wednesday afternoon in northeast Fresno County at the intersection of Tollhouse and Sample.
Investigators tell Action News a 52-year-old man was collecting wood with his golf cart and attached trailer when he got too close to a drop-off. He then fell 400 feet.
"We found him and saw that he had lost control going down the side of the hill. His cart had overturned and trapped him underneath the vehicle," Sgt. Craig Hinch of the California Highway Patrol said.
Investigators say that alcohol was not a factor in the accident.