Avalanche Forecast

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

The rather largo weather pattern that has been in place for the last week is being swept out of the province Monday setting the stage for an active weather week influenced by SW flow for the southern interior. Monday Evening: freezing level tops out around 1700m Monday evening as precip begins to fall. 10mm of water are expected, most of which will fall as rain as high as 1500m. Alpine elevations should receive 15 or so cm of snow. Winds should be moderate out of the NE, switching SW overnight. Tuesday: Freezing levels remain near 1500m, trace of precip expected. Treeline winds light out of the S, SW, Alpine winds Moderate, SW. Wednesday: Freezing level 1500m, 3mm water expected during the day. Winds light SE at treeline, moderate S in the Alpine. Look for clearing skies Thursday AM with precipitation expected to start back up in the afternoon.

The strong spring sun initiated an avalanche cycle Sunday that included everything from small sluffing to size 2.5 avalanches in the afternoon. A natural cornice fall size 2.5 was reported from the high alpine on a NW aspect on Saturday. On Friday, a very large avalanche was triggered by a cornice in Gorman Lake (Dogtooth Range). It was wide, deep and covered sled tracks. Photos here: http://bit.ly/GMOYCv . There were four other close calls in the Purcell Mountains this week, all involving very large slabs releasing either from a distance or with a light load. On Thursday, a snowmobiler remotely triggered a size 3.5 slab on an east aspect at 2400m at Oldman Creek, east of Quartz Creek (video here http://bit.ly/GLHIbg). It failed 1-2 m deep, was 200-300 m wide and ran full path, taking out mature timber. A second slope also failed, either remotely or sympathetically.

Warm alpine temperatures combined with strong solar radiation on Sunday caused moist snow up to about 2400 metres. The major concerns are the mid-February persistent weak layer, buried 1-2 m deep, and facets at the base of the snowpack. The February layer demands respect right now. It is very touchy and can be triggered remotely or by a light load on a variety of aspects, creating frighteningly large avalanches.