New wind slabs are expected to form this weekend as a weak storm progresses. Continually assess local conditions as you travel and use extra caution as you transition into wind affected terrain.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
Mostly cloudy conditions are expected on Saturday as a storm system approaches the region. Light intermittent snowfall is possible during the day with alpine winds increasing to moderate to strong from the SW. Treeline temperatures are expected to be around -15C during the day. The main part of the storm is expected to affect the region Saturday night and Sunday. 10-15cm of snowfall is possible for the snowy parts of the region. Alpine winds are expected to remain moderate to strong from the SW and treeline temperatures will climb to around -10C. Unsettled conditions are expected on Monday as the remnants of the storm are pushed out by a ridge of high pressure.
Avalanche Summary
No new avalanches have been reported since Monday.
Snowpack Summary
20-40cm of low-density snow overlies soft wind slabs which formed last weekend. The few observations we have received suggest a good bond within the storm layers in the upper snowpack. New wind slabs are expected to form this weekend as winds increase with the approaching storm. Between 80 and 130cm below the surface you'll likely find a weak layer of well-developed surface hoar which was buried in early December. This layer is most widespread at lower elevations (between 1100m and 1700m.) Snow pit tests suggest that human triggering of this interface has become less likely. That said, if it does fail the overlying slab is stiff enough to propagate over a wide distance. Below this layer, the snowpack is thought to be generally strong and well-settled.
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.