On April 10, 1999, approximately 1230 mountain daylight time, N4036E, a Piper PA-18, sustained substantial damage when it ground-looped after landing off-airport near Boulder, Montana. The private pilot and his passenger were uninjured. The flight, conducted in visual meteorological conditions, had originated at Bozeman, Montana. There was no flight plan filed for the flight, and no report of the ELT actuating. The pilot stated that he was landing on a north-south dirt road to the south, near the Carey ranch, southeast of Boulder. He stated that the winds were calm and the airplane rolled into a dust devil and directional control was lost. He said there were no ruts or ditches on the road. The pilot reported that all his flight experience was in tailwheel airplanes, and did not report any mechanical malfunctions with the airplane.