Regions
Banff Yoho Kootenay.
Remote and human triggering is still possible, although the recent natural cycle has subsided. Travel conditions remain challenging based on an unconsolidated snowpack. AB
Weather Forecast
A slight warming trend is entering the forecast region (3000m -16). Also, not more than 3cm of snow is expected on Friday, which will not affect the danger rating.
Snowpack Summary
Recent storm snow has settled into a soft slab and has significant wind affect in open terrain at treeline and above. The lower half of the snowpack is a complex and poorly structured & comprised of the facets (Nov 24th) at the interface of the recent storm snow and a series of thin crusts (Nov 6th) and depth hoar at or slightly above the ground.
Avalanche Summary
Avalanche control yesterday produced a size 2.5 avalanche on the Sunshine roads path. This is indicative that triggering is still possible. No observations or reports of avalanches today.
Problems
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.