On June 11, 1998, at 1215 mountain daylight time, a Rolladen-Schneider LS-6 glider, N511M, was substantially damaged after impacting terrain during landing at Green River Municipal Airport, Green River, Utah. The private pilot, the sole occupant onboard, was seriously injured. The glider was being operated by the owner under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local personal flight which had originated approximately 3 minutes before the accident. No flight plan was filed. According to the co-owner of the glider, the pilot was given an auto-tow launch from runway 13 (5,600 feet X 60 feet, elevation 4225 feet) and he believed that the pilot released at approximately 700 feet agl. The co-owner observed the glider circling southwest of the runway, losing altitude. The pilot stated that he encountered "heavy sink almost immediately after tow release." The co-owner further observed the glider fly over runway 13, but "was too high to land straight ahead." The pilot further reported that "he turned left to return to the runway and the glider began to rotate left." The pilot told the Investigator-In-Charge (IIC) that he "got the right rudder in and the rotation stopped within 90 degrees." The co-owner stated that "an apparent wind gust from above or behind caused the glider to nose down." The pilot stated that "just as the rotation stopped, the left wing tip impacted the ground." The glider came to rest facing approximately 220 degrees. The left wing and the tail section were substantially damaged. The canopy, flight deck, and instrument panel were destroyed.