On August 23, 1999, at 1510 hours Pacific daylight time, a Burkhart Grob G 103 Twin II, N8013K, landed hard after encountering a dust devil while landing at the Crystal Gliderport in Llano, California. The glider, operated by Great Western Soaring School, Llano, was substantially damaged. The student glider pilot, who held a private pilot certificate with an airplane single engine land rating, was not injured. The local area instructional flight was conducted under the provisions of 14 CFR Part 91 and had originated from the Crystal Gliderport at 1349. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he was preparing to land on runway 25, and that the tetrahedron indicated the wind was coming straight down the runway. As he was flaring approximately 10 feet above the runway surface, he observed a dust devil move onto the runway directly in front of him. He applied down elevator control but the glider ascended about 50 feet above the ground into the dust devil. The pilot stated that the glider stalled and landed hard on the runway numbers. The glider's right wing tip caught on the ground and the glider ground looped 180 degrees on the runway. During this process, the empennage broke off at the aft fuselage boom just forward of the fin. The tail wheel and nose wheel tires blew out. Ground witnesses provided statements that were consistent in the observation that a "large and violent dust devil" touched down on the runway in the path of the landing glider just as it was in the landing flare.