Strong winds at ridge top elevations in the Icefields area are increasing the slab avalanche danger.
Weather Forecast
Strong Southwesterly winds at elevation with the possibility of 10cm of new snow in the Icefields area. Temperatures will remain cool through to the weekend.
Snowpack Summary
Windslabs in the alpine are the primary avalanche concern. These are more likely to be encountered in the Columbia Icefields area where the strongest winds have been observed. In the Marmot Pass area on December 18th, surface slabs failed with a moderate shear near treeline elevations. The mid snowpack remains supportive for the time being.
Avalanche Summary
No new avalanches have been observed in the past 24 hours.
Confidence
Forecast snowfall amounts are uncertain on Thursday
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.