The glider was substantially damaged during a forced landing following an aborted aero tow at 1245 Mountain time. The Private pilot and passenger were not injured; visual conditions prevailed. The glider pilot said the tow started normally. He said the towplane started pulling up and then touched back down and the glider pilot saw a puff of smoke. He elected to release and perform an emergency landing at an altitude of approximately 75-100 feet. The pilot said that after turning 90 degrees right, the glider was close to the ground so he leveled the wings and tried to flare and the glider impacted terrain and ground looped. The right wing was severed from the aircraft and the fuselage was found in two pieces, separated just aft of the cockpit.