Natural loose snow avalanches were observed on very steep terrain in thin snow pack areas. Ice climbers should evaluate routes and approaches that may have similar conditions above them.
Weather Forecast
Cold cloudy conditions with light flurries and light to moderate NW winds can be expected as arctic air moves into the forecast area.
Snowpack Summary
Up to 10 cm of new snow in the Icefields area has buried recently formed wind slab on NE aspects, tree line and above. The mid snowpack remains supportive however it is quickly loosing strength in shallow snowpacks.
Avalanche Summary
Natural loose snow avalanches have been reported on steep slopes below tree line where the snowpack is thin. Loose snow avalanches to size 2 were the result of avalanche control work on the Parkway on December 21st. The control work was on thin steep below tree line slopes.
Confidence
Wind effect is extremely variable on Saturday
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.