Regions
Banff Yoho Kootenay.
Better skiing can be found due to the recent, however there is a poor bond at the storm snow interface and the overall snowpack is quite weak. Avoid larger features in steeper terrain. SH
Weather Forecast
A gradual cooling trend over the next few days with temperatures reaching the-20's by Monday. Expect only trace amounts of snow. Light alpine winds from the East/NE through the forecast period.
Snowpack Summary
Recent winds have created small wind slabs in the alpine which sit over the Dec 18 layer of crust, facets and/or surface hoar depending on the location. A poor bond exists at this interface. At the base of the snowpack weak crusts and facets exist which are still a concern.
Avalanche Summary
Following the storm last week avalanches up to size 2.5 were observed with propagations up to 200 m, occasionally stepping down to the basal facets/crusts.There was significantly less avalanche activity around the Banff area. The Lake Louise region and West received the bulk of the snow with a subsequent increase in activity.
Confidence
Due to the number and quality of field observations on Saturday
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
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.