Despite the MODERATE hazard rating, this is a bit of a tricky time due to the highly variable snowpack. Most likely trigger spots will be in thin snowpack areas, which could produce very large avalanches.
Weather Forecast
Wednesday will begin with a frosty -22 Celsius, warming to about -8 Celsius by afternoon. Skies will be mostly sunny and winds will be light from the West. Some weather models are predicting that light flurries will move in Wednesday afternoon and continue Thursday and Friday with accumulations near 15cm.
Avalanche Summary
No new avalanches observed or reported today.
Snowpack Summary
5 to 10cm of low density recent storm snow overlies a very dense mid-pack of between 50 and 70cm at Treeline. Under this mid-pack is between 50 and 70cm of very weak facets, including depth hoar. The strong mid-pack is bridging over the weak layer in much of the region, but forecasters and being very cautious in shallow snowpack areas due to the higher likelihood of finding a weak spot (buried rock, thin spot, buried tree/shrub) that could act as a trigger. While triggering this deep persistent slab has a relatively low probability, the consequences will be high. Any avalanche that steps down to the basal layers will be large and destructive.
Problems
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.
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.