On June 16, 2002, about 1545 eastern daylight time, a Schleicher ASK21 glider, N341KS, was substantially damaged when it impacted trees, then terrain, while maneuvering near Woodstock, Virginia. The certificated commercial pilot and the passenger received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the flight that departed the Front Royal-Warren County Airport (FRR), Front Royal, Virginia. The local personal flight was conducted under 14 CFR Part 91. After he departed behind a tow airplane about 1530, the pilot flew toward the Massanutten Ridge. The glider was released from the tow airplane in the vicinity of Signal Knob, and flew about 10 miles along the ridge. In a written statement, the pilot reported that while he was ridge soaring along Massanutten mountain, he "failed to recognize that the wind speed necessary to generate sufficient orographic lift had diminished." He also stated that he "failed to execute an alternate plan of turning toward the Shenandoah Valley, while he had enough altitude above the trees to safely make the turn." The pilot reported that when he attempted to make the turn toward the valley, "into very weak ridge lift," the glider stalled and "mushed" into the trees. The glider slid through the trees, then impacted the ground in a nose low attitude. The pilot also stated that he evaluated the weather conditions prior to his departure by visual observation, and talking to other pilots. He noted there was an overcast cloud layer about 4,000 feet, and the shadows from the clouds demonstrated there was "good orographic lift" in the area. The winds at the surface were from 270 degrees at 10 knots, and at the ridge top they were from 270 degrees about 15-20 knots. The pilot reported approximately 445 hours of total flight experience, 186 of which, were in make and model. He also reported no mechanical deficiencies with the glider. According to the pilot, the glider sustained substantial damage to both wings, the fuselage, and the horizontal stabilizer. Weather reported at Winchester Regional Airport (OKV), Winchester, Virginia, 24 miles to the northeast, at 1540, included wind from 280 degrees at 12 knots, gusting to 17 knots, 10 miles visibility, and clear skies.