Regions
Banff Yoho Kootenay.
Stormy weather is expected to affect the region over the next few days. Slab formation has begun over the December 3 interface and we will be closely watching how the incoming snow bonds to this highly variable layer.
Weather Forecast
A series of systems will bring moderate amounts of precip in several pulses to the region through Thursday. Moderate to strong westerly winds will continue in the alpine and freezing levels look like they should peak Tuesday with the influence of the south westerly flow.
Snowpack Summary
The Dec 3 interface is now buried by 10-20cm in the alpine. This interface consists of facets BTL, widespread wind effect above TL, suncrusts on steep S and SW aspects, and surface hoar up to 20 mm found in some locations up to 2000m. South and Southwest winds in the moderate range are building soft slabs in the lee of alpine features-.
Avalanche Summary
Small windslabs local to ridgecrests are reactive to skier traffic in the alpine and at treeline.
Confidence
Timing, track, or intensity of incoming weather system is uncertain
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.