Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Regions
Waterton Lakes.
Recent snow has formed a slab overloading weak snow below treeline. This problem is compounded by the newly burnt forest, allowing wind to stiffen the snow all the way to valley bottom.
Weather Forecast
Saturday: Mix of sun and cloud with light Northeast winds. Alpine High -15Sunday: Sunny with cloudy periods, light East winds. Temperature inversion, with an Alpine high of -19.Monday: Cloudy with isolated flurries, with up to 10cm on the front ranges, and less along the divide. Alpine high of -18
Snowpack Summary
The midpack remains strong in deep snowpack areas, but is acting as a slab above deep weak layers in shallower areas that is reactive skiers mainly at below treeline elevations where melt freeze crusts have been preserved. Continued snowfall on Saturday is burying windslabs formed by recent Westerly winds.
Avalanche Summary
We received a second hand report of skier triggered avalanches below treeline on Mt. Bertha on Thursday failing on facets above a crust deep in the snowpack, or basal facets. A natural size 2 slab was also observed below treeline in a steep and shallow snowpack feature in the Cameron Lake area that failed on similar weak layers earlier in the week.
Confidence
Problems
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.
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.