N725V

The pilot and his passenger had been traveling across the country visiting backcountry airstrips. They had spent two nights at a backcountry airstrip and decided to go on a day flight to one of the other airstrips in the area that was 1,500 feet in length by 50 feet wide. After surveying the landing area, the pilot stated that as he neared the approach end of the runway, he was approximately 20 feet above ground level when the airplane dropped straight down. The pilot indicated that his airspeed was slow and that he most likely encountered a downdraft. This resulted in the airplane landing hard on the runway surface and the airplane porpoised, prior to impacting rising terrain and trees. There were no mechanical malfunctions reported.