The two avalanche problems have been slow to improve, hence the continued CONSIDERABLE danger rating. Cautious route-finding is advised in the Alpine and open areas at Treeline.
Weather Forecast
Very cold conditions tonight should give way to a more moderate day on Tuesday with Alpine temperatures climbing to -13 celsius with a temperature inversion (colder in the valley floors). Wind chill will still be a factor as winds from the NW will reach 30km/h. No precipitation is expected for the next several days.
Avalanche Summary
Nothing new today.
Snowpack Summary
Trace to 2cm of new snow in past 24hrs. The Dec 13th rain crust, which exists at 2200m and below, is buried 15 to 30cm depending on elevation. Where wind slab conditions exist this rain crust provides a good sliding layer. The weak basal layers, including the November rain crust, are still a cause for concern. Isolated avalanche activity in the past several days indicate that this layer is still trigger-able. While the probability of triggering the basal layers is low, the consequences of a full depth avalanche is significant.
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.