Expect to find wind slabs from recent snow that fell with strong winds. Observe for signs of instability before entering a slope, such as cracking, whumpfing, and avalanche activity.
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
SUNDAY: Cloudy with light snowfall, accumulation 2 to 5 cm with possible localized higher amounts from convective flurries, light to moderate southwesterly winds, alpine temperature -8 C, freezing level 900 m.MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm, light northeasterly winds, alpine temperature -15 C, freezing level 600 m.TUESDAY: Partly cloudy with light snowfall, light westerly winds, alpine temperature -8 C, freezing level 800 m.
Avalanche Summary
On Saturday, a large slab avalanche was observed in a treeline-like terrain feature in a forest burn, but at below treeline elevation. The feature is convoluted and of convective-nature. It is suspected that it was triggered by a snowmobiler. Check out the MIN report just south of Crowsnest Pass for photos. Other small wind slabs were noted in the region on all aspects.
Snowpack Summary
10 to 25 cm of new snow fell at higher elevations on Friday, with associated strong westerly switching to easterly winds. The precipitation fell as rain at lower elevations, which froze into a melt-freeze crust.About 50 cm deep, a crust is found up to 2200 metres. At a similar depth, a layer of surface hoar is found on shaded aspects at treeline in parts of the region.The midpack is well-settled and strong. This overlies sugary facets in thin snowpack areas.
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.