A week of heavy snowfall and strong winds has left large storm slabs and cornices primed for human triggering. Avoid overhead hazards and stick to mellow terrain.
Summary
Confidence
Moderate - Due to the number of field observations
Weather Forecast
We're looking at occasional flurries and cool temperatures throughout the forecast period. TUESDAY: Flurries with up to 5 cm of new snow, 20-40 km/h southeast winds, alpine temperatures around -9 C. WEDNESDAY: Flurries with 5-10 cm of new snow, 20-30 km/h east winds, alpine temperatures around -8 C. THURSDAY: Cloudy with scattered flurries and up to 3-5 cm of new snow, 30-50 km/h east winds, alpine temperatures around -12 C.
Avalanche Summary
Cornices are large and remain easy to trigger. See
here for a great MIN post from Sunday illustrating just how surprising the results can be.Several size 1.5 to 3 natural and explosives triggered avalanches were reported on Saturday. Aspects were east through northwest, from 1500m to ridgetop.A widespread natural avalanche cycle occurred on Friday night, with many size 2-3 cornice triggered avalanches on north and east aspects. Natural activity is expected to taper off, but storm slabs will remain possible for human triggering.
Snowpack Summary
Another 10-20 cm of snow fell on Sunday into Monday, bringing the weekly total to over 115 cm. Strong southwest winds have extensively redistributed the snow and formed large brittle cornices.The new snow came in "upside down" (heavier, denser snow over lighter snow) and is rapidly settling into a slab which sits over a variety of old surfaces including surface hoar, facets, stiff wind slabs, sun crusts, and a rain crust below 1900 m.Isolated basal weaknesses may still exist in shallow snowpack areas and appear to isolated to north-northeast aspects in the alpine.
mgrist,
Avalanche Canada
