On August 19, 1997, about 1630 mountain daylight time, N52AS, a Blanik L-13 glider, operated by the Hellgate Soaring Society, struck a taxiway sign during landing rollout and was substantially damaged near Hamilton, Montana. The private pilot and his passenger were not injured. Visual meteorological conditions prevailed and no flight plan had been filed. The personal flight departed Hamilton and was conducted under 14 CFR 91. According to an eyewitness (statement attached) who is a representative of Hamilton Aviation, Inc., the glider turned off of "...runway 34 at the A-1 exit at high speeds, estimated at thirty miles an hour. The winds favored [runway 34] at light and variable. At that time the wing of the glider missed the runway lights, but impacted with the exit A-1 sign...." According to a certified flight instructor (statement attached) who was in the traffic pattern behind the glider, no corrections were necessary for a cross wind, and there was a "slight breeze...no more than five knots..." from the northeast as indicated by the wind sock. The certified flight instructor also stated that as he observed the glider land on runway 34, he expected the glider pilot to continue his landing roll out to the end of the runway. Instead, he observed that the glider had turned off onto a taxiway well before the end of the runway. In a written statement to the Safety Board, the pilot stated: "... [I] landed properly and safely. While taxiing to tie down area a wind gust slammed down my left wing which struck down the airport [runway] signs.... " The pilot also reported that there were no preimpact mechanical malfunctions.