Reactive Coastal Snow

brian.thornburn

Skier triggered slab avalanches witnessed

Snow conditions were: Deep powder, Heavy. Weather conditions were: Cloudy, Foggy. We rode: Alpine slopes, Mellow slopes, Open trees, Steep slopes. Riding quality was amazing.

Avalache Conditions: Slab avalanches today or yesterday. 30cm + of new snow, or significant drifitng, or rain in the last 48 hours.

Incident

Writer triggered avalanche by skiing aspect after ski cutting failed to propagate. Writer caught by fast moving slab, was pushed forward after skis were buried. Snow piled above writer up to neck, but trunk was not compressed. Was able to free arms and clear snow around shoulders, but unable to further move. Companions were able to extricate writer within 5 minutes and no injuries occurred. Avalanche was 10m wide by 25m long, writer was buried due to terrain trap: aspect transitions abruptly on flat surface.

Avalanche

Ski cut performed to test slope. Cuts on similar aspects in the same area saw reactivity, class 0.5-1 avalanches. This slope saw no reactivity, so writer skied the slope and triggered a class 1 slide that resulted in partial burial. Avalanche was 10m wide by 25m long. Crown depth approximately 40cm