Warm temperatures below treeline will create isothermal conditions resulting in increasing possibility of loose snow avalanches. These temperatures will also increase the hazard at treeline and above.
Weather Forecast
The freezing level will rise to 2000 m Thursday. Light precipitation will continue with sunny breaks through to Saturday. Forecast models are uncertain for the weekend but another large pulse of precipitation is possible on Saturday.
Snowpack Summary
There is a wide variation in the snowpack across the forecast region. In the Icefields Area, there is significant snow available for transport. SW winds will be forming wind slabs below ridge lines and along gulley features. Up to 1 meter of storm slab is sitting over the Jan 29 rain crust on all aspects at treeline and above.
Avalanche Summary
Minor sluffing continues out of steep terrain.
Confidence
Timing, track, or intensity of incoming weather system is uncertain 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.