On June 17, 1999, approximately 1145 mountain daylight time, a LET 13 (Blanik) glider, N70741, was substantially damaged during landing on runway 12 (sod) at Belgrade, Montana. The certificated flight instructor and his dual student were uninjured. Visual meteorological conditions prevailed at the time of the accident. The flight had departed Belgrade airport (towed by an airplane) about fifteen minutes before the accident. The flight instructor stated that the glider was cleared to land on the sod runway 12 at midfield left downwind. "After turning base, just before turning to final, the tower asked the glider to execute a 360 degree turn due to a Tomahawk that had been cleared to land runway 30. After the 360 the tower asked the glider to execute another 360 degree turn due to the Tomahawk still taxiing on 30. I took control of the glider on the second turn around because the student was uncomfortable with the situation and the low altitude. I asked the student (one radio in front) to call the tower and confirm 'cleared to land' and the tower would not answer back until the Tomahawk had cleared the runway. Finally, cleared to land again I got the student set up on low final and gave the plane back to the student and began a demonstration of ground effect to stretch the landing (wanting to get the glider near the other end of the runway for the tow off of runway 30 sod). Sometime during the pattern the tower had asked the tow plane pilot to switch to ground frequency and asked him to immediately remove the glider off the north side of the runway upon rolling out (student flying the plane). The tow pilot entered the runway in front of the glider and motioned to turn the glider off the runway. I started to give instructions to the student to put the left wing down to start the turn and realized we were going too fast to safely make a turn without hitting the tow pilot. So I again took control of the glider and tried to make a right turn (away from the tow pilot and tow plane but toward the 30 runway). I got the left wing over the tow pilot and over most of the tow plane (which was parked off the north edge of the runway). But the wing tip of the glider struck the prop of the tow plane and caused damage to the underside of the glider's wing. While the instructions from the tower were distracting and caused the glider to be low on final, I think the communication to the tow pilot (and not the glider) caused the tow pilot to enter the runway and caused the evasive maneuver that contributed to the accident. Despite the confusion a safe landing was underway until that time; I should have rolled out straight ahead and made the tow pilot jump clear and then the collision would have never occurred." The tow plane pilot stated that after releasing the glider at 3000 feet, "I returned and landed on 12 sod and was instructed to contact Ground control on 121.8 after parking. "After parking in the same runup area I shut down and contacted ground control. The controller instructed me to have the glider pull off the runway to the spot I was parked. He said he could not use the main runway with the glider on 12/30 sod. With the tow plane in the runup area I was unsure where he wanted us to put the glider. After asking, he said anywhere that was as far off the runway as the tow plane. From this point on I was out of the tow plane and away from the radio. "After the glider came in to land, I stood by the wing tip of the tow plane. I assumed the tower would have told the glider pilot the same instructions he gave me. Therefore, I expected the glider pilot to be prepared for my hand signals directing him off of the runway. However not having been briefed by the tower, he landed longer and faster than usual to fit the flight instruction that his student required. "Seeing my signal, the glider pilot attempted to comply and began a turn toward the side of the runway. Realizing he was too fast to make the turn he changed his mind, reversed his turn back to the runway. By this point he was also too fast to make this turn without hitting the tow plane. He attempted to raise the glider's wing over the tow plane. However, the prop was too high and was struck by the glider's wing." On contact with the tow plane's propeller, the glider received damage on the left leading edge and aileron.