Careful snowpack evaluation and cautious route finding is essential right now.
Weather Forecast
Temps to remain cool, freezing levels well below treeline, and winds light to moderate from the Southwest. Light snowfall expected to begin on Wednesday, intensifying towards the weekend. The Columbia Icefields area will receive an additional 25cm by Sunday.
Snowpack Summary
The Columbia Icefields received 35cm of low density snow over the weekend. Prior to that the alpine was found to be scoured old snow or hard windslabs. Lots of snow available for transport, and some moderate ridge top transport observed today.
Avalanche Summary
Field patrols in the past few days observed the debris from numerous large avalanches. These avalanches exhibited wide propagation, were primarily found in big East facing alpine terrain, and several were triggered by cornice fall. As the wind begins to push the recent snow around, the likelihood of triggering new slabs will increase.
Confidence
Intensity of incoming weather systems is uncertain
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.
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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.