The Icefields Parkway North of Saskatchewan Crossing and the Maligne Lake road remain closed until avalanche control can taken place on Sunday. Many large avalanches are running and will likely continue to do so throughout the weekend.
Weather Forecast
Colder temperatures over the next 24 hrs with overnight lows of -15 at treeline. Highs on Sunday will be close to -10 with light to moderate southerly winds and snow flurries at higher elevations to 10cm. No significant snowfall forecast next week with cool temperatures and a moderate westerly flow.
Snowpack Summary
Up to 45cm of storm snow has been received across the forecast area during the past 36 hours. Under the influence of light to moderate southerly winds a soft slab is forming at treeline and above. The mid and lower snowpack is unstable, the base of which is weak depth hoar crystals and a rain crust, dating from November.
Avalanche Summary
Avalanche control was stalled due to poor flying conditions. Field teams were able to determine that there was widespread avalanche activity up to size 3. Although the visibility was poor these events seem most prevalent in the alpine from the new storm slab which, as predicted, is stepping down to basal weakness resulting in deep releases.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
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.