On March 11, 2001, about 0900 Pacific standard time, an Eurocopter AS 350 B2 Ecureuil, N189EH, registered to and operated by Era Aviation Inc. as a 14 CFR Part 135 on demand air taxi service, rolled over after landing on a remote snow covered mountain site on Silverstar Mountain located seven miles west southwest of Mazama, Washington. Visual meteorological conditions prevailed at the time and a company visual flight rules flight plan was in effect. The helicopter was substantially damaged and the commercial pilot and three passengers were not injured. The two remaining passengers received minor injuries. The flight originated from Mazama Heliski Lodge about 15 minutes prior to the accident. In a written statement prepared by Era Aviation's Vice-President - Safety, the purpose of the flight was to drop off skiers at a prepared mountain ridge landing site. The landing site was a small ridge on a large rock outcrop on the north side of the mountain. The area had been leveled and four 4-foot high stakes had been placed in the snow with flags attached to act as wind indicators. The pilot had approached the site into the prevailing winds. During the descent at about 50 feet, the wind increased and shifted to the left side. The helicopter began to descend rapidly, and the pilot increased power in an attempt to arrest the rate of descent. Shortly thereafter the low rotor rpm horn sounded and the helicopter touched down just past the normal landing site with "enough force and forward speed to prevent the pilot from holding it on the intended landing site, so he added forward cyclic in an attempt to prevent it from falling of[f] a 30 foot drop." Due to the low rotor rpm, and the inability to maintain altitude, the pilot elected to land the helicopter in a large open snowfield. During the landing, the helicopter settled into the snow and the main rotors contacted the ground. The helicopter subsequently rolled over. The weather at the accident site was reported as high overcast. The wind direction was not indicated, however, the wind velocity was reported at 15-20 knots. No mechanical failures or malfunctions were reported.