ACCORDING TO THE PLT, HE TOOK OFF UPSLOPE INTO THE WIND IN AN EASTERLY DIRECTION. IMMEDIATELY AFTER TAKING OFF, HE MADE A RIGHT TURN TO A X-WIND, & SECONDS LATER, HE MADE A FURTHER TURN THE RIGHT (DOWNWIND). VISIBILITY TOWARD THE EAST WAS ABOUT 1/4 MI, BUT TO THE WEST, THE VISIBILITY WAS GOOD. THERE WAS ONLY 1 VISUAL POINT ON THE HORIZON. THE PLT STATED HE BEGAN A CLIMB FOR VISUAL REFERENCE ON THE HORIZON, THEN NOTICED THE HELICOPTER WAS SETTLING. THE ENG OUT/LOW RPM AUDIO WARNING & LIGHT ACTIVATED JUST BEFORE THE HELICOPTER IMPACTED SNOW COVERED TERRAIN IN A LEVEL ATTITUDE WHILE MOVING FORWARD. A SKID DUG IN & THE HELICOPTER WENT OVER ON ITS TOP. SUBSEQUENTLY, THE HELICOPTER WAS COVERED WITH SNOW & WAS NOT RECOVERED; THEREFORE, THE CAUSE OF THE APPARENT POWER LOSS WAS NOT DETERMINED. THE ELEVATION OF THE CRASH SITE WAS ABOUT 6800 FT.