According to the pilot, there were some areas of turbulence during the glider's aero tow to 3,000 feet, but the tow was uneventful. The flight was then smooth until descent to about 1,200 feet above ground level, when conditions became "bumpy." Upon entering the traffic pattern for runway 24, the pilot increased normal approach airspeed by 10 knots in anticipation of gusty headwinds on final approach. The approach then proceeded "normally" until short final, when the glider encountered a "rogue" wind gust that "violently" rolled it about 90 degrees to the right, heading it away from runway centerline. By the time the pilot was able to level the wings, the glider was too low, necessitating an off-airport landing into small trees that resulted in left wing spar damage. Winds, recorded at a nearby airport about the time of the accident, were from 260 degrees true at 13, gusting to 19 knots. The pilot did not report any preexisting mechanical anomalies that would have precluded normal operation.