Wind slabs and cornices are the main concern for today. The avalanche danger will rise this weekend, peaking on Saturday as the storm settles in.
Weather Forecast
Cloud building today as a storm approaches from the pacific, snow is expected this afternoon continuing over the weekend, with the bulk of the snow arriving tonight and tomorrow am. Temps will reach -11 today, with moderate winds from the north east. Forecast models are uncertain on precip amounts, south of us will see the most precipitation.
Snowpack Summary
Previous strong Southerly winds have caused extensive wind effect in the alpine. Conditions are highly variable from wind scoured, wind slabs, hard slabs and deep wind drifts. Surface hoar to size 3 was found in profiles Tuesday underneath the wind effected snow. At treeline and in very sheltered alpine locations the snow surface is undisturbed.
Avalanche Summary
There was a natural avalanche cycle earlier in the week associated with the strong winds and 10cm of new snow. Numerous avalanches from size 2 -3 were observed to run into their runouts. In the backcountry there was reports of both natural and human triggered windslabs. A cornice triggered avalanche was also observed Tuesday below Avalanche pk
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Saturday
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.