The pilot stated that the purpose of the flight was for him to take his cousin, the sole passenger, around the local ski area. After departure, the glider was towed to about 9,000 feet mean sea level (msl) and adjacent to the ski area. The pilot maneuvered the glider in a 300-degree turn to the right and realized that he was at a lower altitude than the ridge. He continued toward the ridge in an effort to gain lift off of the canyons. As the glider continued to lose altitude, it descended below 6,000 feet msl and the pilot began to look for terrain that would be favorable for an off-airport landing. After deciding on a location, the pilot deployed the airbrakes and with the glider about 10 to 15 feet above ground level (agl), he intentionally stalled. The glider mushed into the ground with little horizontal speed. During the accident sequence the glider incurred substantial damage to the tail boom and wings. The pilot reported no pre impact mechanical malfunctions or failures with the glider that would have precluded normal operation.