A Buffalo Airways Beech King Air suffered a runway excursion on landing at Kugaaruk Airport, Canada. At 12:16, the aircraft departed Cambridge Bay Airport for Kugaaruk (CYBB). The first officer was the pilot flying. At 13:19, when the flight was about 80 nautical miles from CYBB at flight level 210, the flight crew called the CYBB community aerodrome radio station. The flight crew received the runway surface condition report and were informed that the winds were from 200ø true, at 24 knots gusting to 33 knots. At 13:20, the community aerodrome radio station operator called the flight crew and relayed the CYBB 1300 weather observation, reporting that the horizontal visibility was 1/4 statute mile in light snow and blowing snow and that the vertical visibility was 400 feet. The flight crew noted that the visibility had decreased since their departure from Cambridge Bay but continued the approach. The reported wind would result in a 12-to 16-knot crosswind component from the left on runway 23. The captain took control at 13:27, at the start of the descent, and descent checks were carried out. The captain transferred control back to the first officer at the initial approach waypoint, DATLA, and briefed for a pilot-monitored area navigation (RNAV) approach to runway 23. From the intermediate approach waypoint to the missed approach waypoint the approach is flown on a track of 244øT, which is offset 15ø from the runway heading of 229øT. When the runway is acquired visually at or before the minimum descent altitude (MDA), a left turn is required to align the aircraft with the runway heading. During the descent the flight crew activated the runway lights and the precision approach path indicator (PAPI) system via the aircraft radio control of airport lighting system (ARCAL). The captain set the flaps to the approach setting (40%), and the first officer flew the descent. When the captain then confirmed visual contact with the runway, snow was blowing across it at an angle from left to right. The runway itself was apparent as a black shape within the blowing snow; however, the runway lighting and PAPI were not observed. The captain set the flaps to the land setting (100%) and then, as part of the pilot-monitored approach procedure, assumed control of the aircraft as the pilot flying. The first officer looked up from the instruments and observed, through the blowing snow, the runway as well as the community aerodrome radio station and airport apron ahead and off to the left. The aircraft crossed the runway threshold at 100 knots indicated airspeed. As the captain flared the aircraft, the first officer warned the captain of snowbanks off to the right side of the runway. At 13:50, when the right main landing gear touched down, the aircraft veered to the right and departed the runway surface. The right wing contacted snowbanks and the aircraft turned approximately 90ø to the right before colliding nose first with a high snowbank. Both crew members, who were not injured, exited through the cabin door. The aircraft was substantially damaged; however, the freight remained secure. The emergency locator transmitter (ELT) did not activate and there was no fire. Findings as to causes and contributing factors 1. Approaches to airports north of 60øN latitude are not restricted by ground visibility and, as a result, the flight crew continued the approach when the reported visibility was ¬ statute mile, which is lower than the published advisory visibility of 1? statute miles for this approach. 2. The flight crew believed that the lack of an approach ban permitted a landing, and landed at Kugaaruk Airport even though the reported ground visibility was below the minimum aerodrome operating visibility. 3. The offset approach, the crosswind component from the left, and the moving-runway illusion created by the blowing snow, all contributed to the aircraft’s alignment with the right side of the runway. 4. The aircraft touched down near the right edge of the runway and, when the right landing gear impacted the deeper snow along the runway edge, the aircraft veered to the right and departed the runway surface. 5. The snow depth adjacent to the runway was allowed to exceed the limits dictated by the airport operator’s Winter Maintenance Plan. Consequently, the aircraft sustained additional damage when it departed the runway surface.