20 cm of snow expected overnight. If more snow falls than expected, the avalanche danger will rise to High in the Alpine.
Weather Forecast
Heavy snow to begin Saturday night with 20 cm expected. Winds will shift to northerly and will drop to light. Temperatures will fall as the snow begins. The storm will be short lived and be finished sometime before noon on Sunday. By Sunday afternoon the winds will shift back to light westerly, with cool temperatures and light flurries.
Snowpack Summary
Soft slabs have formed immediate below alpine ridgelines from previous moderate to strong West winds. 80+cm of snow has fallen since Wednesday. At treeline, soft slabs are sitting on a thin suncrust that is buried 80 cm deep in wind exposed south facing terrain. Below treeline, 20-30 cm of unconsolidated snow is present over a base of weak facets.
Avalanche Summary
Large natural slab avalanches have run on steep alpine slopes. Several large cornice failures have been observed in the past 48 hrs. At treeline and below, mild temperatures and solar exposure provided the trigger for small loose wet slides south of the Icefields.
Confidence
Forecast snowfall amounts are uncertain on Sunday
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.