On December 10, 2000, about 1400 Pacific standard time, a Kaman K-1200, N317KA, sustained substantial damage subsequent to a dynamic rollover while maneuvering at the Prineville Airport (S39), Prineville, Oregon. The Helicopter is registered to US Bancorp Leasing & Financial, and operated by Grizzly Mountain Aviation of Prineville, Oregon. The helicopter was being operated as a visual flight rules (VFR) positioning flight under Title 14 CFR Part 91, when the accident occurred. The commercial pilot, the sole occupant of the helicopter, was not injured. Visual meteorological conditions prevailed and no flight plan was filed. There was no fire and no report of ELT activation. The pilot reported that while maneuvering for departure, the helicopter began to drift to the left due to wind conditions. While attempting to correct the situation, the helicopter's left main landing gear hit the ground and the strut collapsed. The helicopter subsequently rolled over coming to rest on its left side. The helicopter sustained substantial damage to the fuselage, tail boom and rotor blades. The 1356 METAR observation at Redmond, Oregon, (11 miles southwest of the accident location) reported winds from 310 degrees true at 17 knots gusting to 21 knots. The pilot reported that the winds, at the time of the accident, were from the southwest at 15 knots, gusting to 29 knots. The pilot reported that there were no pre-accident mechanical failures that contributed to the accident.