Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
Kananaskis.
A large scale natural avalanche cycle is starting to taper off. However, the snowpack is primed for human triggering. Choose conservative terrain.
Confidence
High.
Weather Forecast
Monday will be a mix of sun and cloud with very light flurries in the morning. Temperatures in the Alpine should rise to -8°c with generally light winds. Not too much snow is expected for Christmas.
Avalanche Summary
No new avalanches observed today, but there is evidence of a large recent avalanche cycle up to size 3 primarily on East and North aspects over the past few days. Wide propagations have been observed and some slides have reached the valley bottoms.
Snowpack Summary
Strong westerly winds have formed widespread wind slabs in the Alpine and at Treeline, with many slabs up to 120cm thick. The Dec 10th interface of surface hoar and/or facets is the most active layer at the moment, and has been the failure plane for numerous recent avalanches. Look for this layer down 50 to 100+cm in the snowpack. The basal layers remain weak, and although this is concerning there hasn't been as much avalanche activity stepping down to the base of the snowpack in recent days.
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.