The combination of a shallow snowpack, deep persistent slab, and weak layer near the ground add up to a tricky start to the season. Be patient and conservative over the holidays and save the big lines for the new year.Merry Christmas from Jasper!
Weather Forecast
Mild temps with small amounts of snow over the next couple of days. Winds expected to be light to moderate from the Southwest.
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 the basal October 27 rain crust. The crust is 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.
Confidence
Due to the number of field observations
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.