Small loose snow avalanches are common on steep tree line and alpine slopes. These slides are thin but traveling far. Evaluated slopes and ice climbs before committing.
Weather Forecast
Temperatures nearing the freezing level at valley bottoms on Friday. The moderate to strong westerly winds are expected to continue until they ease on Friday night. Expecting cloudy skies with light precipitation and little accumulation.
Snowpack Summary
Moderate to strong SW winds continue to build slab conditions on open tree line slopes and along ridge lines in the alpine. The mid-pack is facetting but remains strong where it is deeper than a meter. In shallow areas, facetting has weakened it significantly.
Avalanche Summary
Surface facets have created numerous small loose avalanches at tree line and above in the Icefields area. These slides have little mass and have not as yet triggered the wind slabs beneath them. No natural slab avalanches were observed today.
Confidence
Due to the number and quality of field observations
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.
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.