Incident Overview
A pilot reported that after waiting for weather conditions to improve, he entered a mountain pass while following a river or its tributary. The flight initially proceeded without issue, but partway through the pass, the cloud conditions lowered very rapidly, causing the pilot to lose visual reference with the waterway.
Maneuver and Impact
Recognizing the loss of visual cues, the pilot attempted to reverse course and exit the pass. However, he observed rising terrain directly ahead. In response, he leveled the wings and applied full engine power in an effort to climb above the terrain. Despite these measures, the airplane was unable to gain sufficient altitude and crash landed on the uphill terrain.
Rescue
The pilot and three passengers survived the event and were rescued the following day. No further details about their condition or the extent of damage to the aircraft were provided in the report.