NTSB Factual Report

The pilot stated that he was aloft over a ridge for 4 hours before the glider experienced a loss of thermal lift. He departed the ridge to the lee side towards a valley with fields in which he intended to land. While on final approach for landing, the glider's upwind wing encountered a gust of wind and subsequently impacted a row of trees before coming to rest in a field; resulting in substantial damage to the fuselage, empennage, and horizontal stabilizer. The pilot reported there were no pre-impact mechanical failures or anomalies of the glider that would have precluded normal operation. He stated that the accident may have been avoided had he remained within gliding distance of a landing site upwind of the ridge in order to avoid lee-side turbulence and sink. The pilot further stated that he overflew several adequate landing sites, but chose to continue in hopes of reaching an airport or a field further from the ridge. As a result, the glider lost altitude and airspeed, which left it "vulnerable to strong gusts."

NTSB Probable Cause

The pilot's improper selection of an off-airport landing site, and his subsequent failure to maintain clearance from trees during a crosswind landing in gusty wind conditions.