Regions
Banff Yoho Kootenay.
Cooler temperatures will lock down the snowpack below treeline this weekend. Be cautious on higher elevation features where the basal layers can be triggered. Ski quality is less than ideal, but its a good forecast for ice climbers. SH
Weather Forecast
The forecast is for a cooling trend throughout the weekend with temperatures staying below freezing starting Saturday. Winds will die down and stay light for the next 3 days. There is the possibility of a couple cm of snow Friday night and Sat. but don't expect much! Beyond that no significant snow is in the short, mid or long range forecasts.
Snowpack Summary
Strong SW winds have stripped windward aspects and created wind slabs in lee terrain in the alpine. Mild temperatures have promoted settlement in upper pack, but lower basal rain crust/facets at treeline and in the alpine remain weak. Warm temps and rain below treeline have promoted rapid settlement and a decrease in snow depths.
Avalanche Summary
No new avalanches observed today.
Confidence
Freezing levels are uncertain on Saturday
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.