At about 1945 Mountain time, the airplane collided with mountainous terrain while maneuvering about 17 nautical miles northwest of Stanley, Idaho. Instrument conditions prevailed at the accident site; no flight plan was filed. The aircraft was substantially damaged and the Commercial pilot, the sole occupant, was fatally injured. The flight departed from Pistol Creek, a private mountain airstrip about 1925. This was a flight of two aircraft that were returning to Stanley after dropping off freight at Pistol Creek. The pilot of the other aircraft reported that the flight encountered fog and clouds while en route and had to circle. Both pilots were in radio contact while circling. The pilot of the second aircraft reported that the accident pilot radioed that he was At the river, starting up Marsh Creek reporting that the clouds were pretty low in here. The second pilot asked the accident pilot if he could turn around. The accident pilot stated, Im too low followed by fog clear to ground. Shortly thereafter, communications with the accident aircraft were lost.