The Icefields Parkway is closed due to high avalanche danger. It will not open until control work has been completed. The new storm snow is unstable and will need time to stabilize. Resist the urge and stick to safe lines on lower angle terrain!
Weather Forecast
The major storm has past however further amounts of up to 20-30 cm are possible by Monday night. Winds are expected to increase to strong from the W to NW. Temperatures will dip Sunday morning then rebound. Temperatures will increase to above freezing with the possibility of rain later in the week.
Snowpack Summary
>35cm of storm snow has fallen since Friday. Moderate SW winds have created deep soft slab conditions in the alpine and open TL slopes. In many locations, these new slabs are sitting on weak basal facets.
Avalanche Summary
Very poor visibility precluded avalanche observation however numerous large avalanches were heard through out the day from the Icefields to Sask Xing. Sluffing of storm snow on steep banks was observed as well as soft slab avalanches to sz 1.5 at treeline.
Confidence
Intensity of incoming weather systems is uncertain on Monday
Problems
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.