Concern remains for the weak layers that exist near the base of the snowpack. These deep persistent weak layers can be very difficult to manage, so a conservative approach to terrain is recommended.
Confidence
Moderate - The weather pattern is stable
Weather Forecast
SUNDAY NIGHT - Cloudy with clear periods / northeast winds, 15-20 km/h, gusting to 50 km/h / alpine low temperature near -14 MONDAY - A mix of sun and cloud / light west winds / alpine high temperature near -10TUESDAY - A mix of sun and cloud / light west winds/ alpine high temperature near -6 WEDNESDAY - A mix of sun and cloud / west winds, 10-30 km/h / alpine high temperature near -6
Avalanche Summary
No new avalanches were reported in the region on Saturday.Previous recent avalanche observations were limited to size 1 thin slabs that released with ski cutting.
Snowpack Summary
5-15 cm of recent snow overlies a weak layer of sun crusts on south facing slopes, and surface hoar (feathery crystals) in sheltered areas. Strong winds have stripped the new snow off of this layer in wind exposed areas and created deeper deposits in lee features. Wind slabs that have formed over this interface are likely to be more susceptible to human triggers.Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack was the culprit in several large avalanches in the region in the past few weeks.
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.