A recent report detailing the events of a backcountry helicopter crash north of Nelson in March points to the cumulative effects of weather in the mishap. The Transportation Safety Board of Canada (TSB) released a seven-page report Nov. 2 on the March 16 tail rotor strike and roll over of an Airbus Helicopters AS350 B3 helicopter in the Kootenay Valley, 35 NM north of Nelson.