The pilot reported that, while on a straight in approach to a remote landing site in an area of mountainous terrain, the helicopter experienced strong gusty wind conditions and down drafts. He attempted to abort the landing to no avail. The helicopter impacted terrain and rolled over resulting in substantial damage to the fuselage, tail boom and main rotor drive system. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation. At the time of the accident, the pilot reported the wind was 30 knots with wind gusts of 40 knots. A passenger reported that enroute to the landing area the pilot stated the helicopter had a 30 knot head wind. The operator’s operating procedures manual states that if the wind is over 30 knots “DO NOT LAND” at the landing zone (LZ). According to the operator, pilots are required to fly over the LZ to determine wind direction and condition before attempting to land.