Regions
Banff Yoho Kootenay.
Recent snow on the Icefields Parkway is making for excellent skiing! We are expecting a juicy storm starting Tuesday around noon which will raise the danger. If it doesn't materialize as forecast, the danger rating may be lower.
Weather Forecast
The next storm is forecast to bring 15 - 30 cm's starting Tuesday around noon followed by a smaller system bringing 5-10 cm's starting on Wednesday at noon with the highest amounts near Bow Summit. Moderate to strong W winds will continue in the alpine and freezing levels peak Tuesday around 1700m with the influence of the south westerly flow.
Snowpack Summary
The Dec 3rd interface is now buried by 30-50 cm of storm snow and is a layer to watch right now. This interface consists of facets and large surface hoar below 2000m, wind effect in the alpine, and suncrusts on steep S and SW aspects. Moderate S and SW winds are building soft slabs in the lee of alpine features. The lower snowpack is well settled.
Avalanche Summary
Small windslabs local to ridgecrests are reactive to skier traffic in the alpine and at treeline. Some cracking observed in a steep below treeline glade today where the Dec. 3rd surface hoar was present. Limited observations in the alpine due to poor visibility.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.