N9353C

The pilot reported that while on the base leg of the traffic pattern his view of the unfamiliar airport, located in a mountain valley, was inhibited due to a hill. As the airport came into view the pilot realized he was too high and he initiated a descent with reduced power and full flaps. The airplane approached the runway with higher than normal airspeed and by the time the airplane touched down; there was not enough runway to stop. The airplane exited the end of the runway and proceeded into a ditch, substantially damaging the firewall. The pilot reported no mechanical failures or malfunctions with the airframe or engine prior to the accident. The pilot further stated the accident could have been prevented by familiarizing himself with the airport.