A snowmobiler was fatally involved in a large (size 2) slab avalanche on Saturday in the Oventop Creek area in the Bone Creek drainage. The avalanche was triggered by the rider at 2100 metres on a south aspect. The crown fracture was 15-100 cm deep, suggesting wind loading was a factor in the incident. The avalanche measured 40 metres wide and ran 300 metres.On Friday a natural size 2 wind slab avalanche was observed on an east facing aspect near 3000 m. Strong to extreme wind Friday night into Saturday may have initiated a natural wind slab avalanche cycle. The North Columbias are the hotspot for human triggered persistent slab avalanches as a weak layer that was buried in mid January continues to be sensitive to human triggers. This layer is touchy enough for avalanches to be triggered remotely (from a distance). Skier and snowmobile triggered avalanches from size 1.5-2.5 have been reported on all aspects at and below treeline almost every day for the last two weeks. The bulk of this activity is occurring below 1900 m. This
MIN report from Monday does a great job of illustrating the sensitivity of this weak layer.