Regions
Banff Yoho Kootenay.
We will see a slow rise in hazard through the early part of next week. New wind slabs building over the basal November rain crust will be the layer to watch. SH
Weather Forecast
A westerly flow will dominate for the forecast, bringing mod-strong alpine winds and increased moisture flow. So far only a few cm are expected each day on Sunday and Monday. On Tuesday forecasts are calling for 10-15cm at higher elevations which will make conditions more prone to human triggering.
Snowpack Summary
Below treeline there is not enough snow yet for avalanches. A supportive rain crust above 1900m formed in early Nov. and lies 20-40cm above the ground. How high this rain crust exists has yet to be determined. This along with surface hoar in some areas is being buried by light snow this weekend. Some lee gullies have thin windslabs.
Avalanche Summary
One small skier triggered avalanche was reported in the Bow Summit Area two days ago. Ski hills are seeing small (1.5) wind slabs 20-40cm thick being triggered in very steep terrain. These aren't yet big enough to bury a skier or climber, but could push you off of a cliff or into a terrain trap.
Confidence
Forecast snowfall amounts are uncertain on Tuesday
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.