A Jazz de Havilland Dash 8-400, registration C-GJZD performing flight QK-8301 from Calgary,AB (Canada) to Seattle,WA (USA) with 78 people on board, was descending towards Seattle when cabin crew reported smoke in the cabin, the flight crew at the same time noticed smell of smoke on the flight deck and declared emergency. Cabin crew reported the smoke in the cabin was becoming thicker. The aircraft landed safely on runway 16R, taxied clear of the runway and performed an emergency evacuation onto the taxiway. The passengers were bussed to the terminal. The Canadian TSB reported emergency services inspected the aircraft and found no visible signs of fire.