A shallow snowpack, deep persistent slab and basal weakness have created a tricky start to the season - conservative route selection and avoidance of big terrain in the alpine is advised. Have a safe and happy holiday season!
Weather Forecast
Mild temperatures with minimal precipitation expected over the next few days. Winds to remain light to moderate from the SW. Freezing level around 1000m.
Snowpack Summary
Variable snow distribution at treeline and above. Wind slabs continue to develop in lee terrain features. Wind slab buried by recent light snow overlies a facetted snowpack and multiple early season crusts. The crusts are distributed unevenly in the forecast area. Facets and depth hoar are just off the ground. This weak base will persist longterm.
Avalanche Summary
Sunday observed several size 2's, likely solar initiated, on cross-loaded gullies above the weeping wall on Mt. Cirrus. They stopped mid-path. Saturday, we observed 2 size 3 avalanches on east facing cross-loaded alpine bowl near Mt. Saskatchewan/Wilson area, 2 size 2.5 on a similar aspect in the Winston Churchill range.
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.