On July 31, 1995, approximately 1500 mountain daylight time, a Rolladen-Schneider OHG LS-3-17, N48EH, was substantially damaged during an off-airport landing near Moriarty, New Mexico. The private pilot was not injured. The personal flight, conducted under 14 CFR Part 91, originated at Moriarty, New Mexico, on July 31, 1995, approximately 1400. Visual meteorological conditions prevailed, and no flight plan was filed. The following is based on the pilot/operator report. The pilot departed the Moriarty Airport via aero tow and shortly thereafter, thunderstorms moved into the area. He flew in a northerly direction to avoid the weather and he noted the sky was becoming overcast, whereas before there had been cumulus clouds. He sighted a field and elected to land. During the landing, the aircraft collided with a cactus, shearing off the left wing. The aircraft groundlooped and incurred additional damage to the fuselage and landing gear.