C-FBLW, a TRK Helicopters Aerospatiale AS350 BA helicopter, was operated under contract to SKEENA Heli-Ski from the Bear Creek Lodge, BC, about 82 nautical miles north west of Smithers, BC. The flight was returning to base camp in the late afternoon with a pilot and 6 passengers on board. As the pilot was maneuvering the helicopter close to the steepening terrain, the cyclic control was moved forward. The nose of the helicopter pitched down and the speed increased to Vne (+/-). The pilot then moved the cyclic back and left, however the helicopter rolled right and pitched up. The cyclic stick was difficult to move, and the helicopter collided with terrain on a steep snow covered slope. The main rotor blades cut a swath through the deep snowpack on the left side, and continued to turn until the pilot shut down the engine (Honeywell LTS 101-700D-2) and applied the rotor brake. All occupants appeared uninjured and expedited egress to the left side due to the steep, downhill slope on the right side. The helicopter was substantially damaged, but the ELT was not triggered to send out an emergency signal.