At approximately 11:30 mountain time, a Cessna 172N struck rising terrain while maneuvering near Durango. The pilot was not injured but two passengers sustained serious injuries. The pilot said he and two friends were on a local sightseeing flight when the pilot executed a left turn to a normally okay route. However, he entered a canyon he could not exit due to rising terrain. The pilot decided to execute a forced landing to a clearing, where the airplane struck trees and terrain.