Avalanche Forecast

Archived

Dec 27th, 2023–Dec 28th, 2023

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Kananaskis, Bow Valley, Highwood Pass, North 40, Spray - KLakes.

Recent winds have done a lot of damage to the upper elevations. Look to sheltered areas at lower elevations for better quality skiing. Ice climbers and scramblers should be wary of lee and cross-loaded features especially in the Alpine.

Confidence

Moderate

Avalanche Summary

Nothing new observed in the last couple of days.

Snowpack Summary

There has been little change to the snowpack in the last 24hrs. Low density snow is found on the surface at lower elevations and in sheltered areas. However, recent winds have created wind slabs in the Alpine and stripped windward slopes down to bare rock in many areas. The early December crust found about 20-35cm down is keeping the skis from diving down into the weaker basal layers of the snowpack, but in areas with denser tree/bush coverage, this crust does not hold the weight of a skier. For better travel conditions look for open planar slopes below approximately 2300m where the crust is supportive. Overall the snowpack across the region is quite shallow, and the basal layers consist of weak facets and depth hoar. This is potentially most concerning at higher elevations where the Dec rain crust disappears and there is simply slab sitting on weak basal layers.

Weather Summary

Expect cloudy skies on Thursday with very isolated flurries. Unfortunately no accumulations are predicted, so snowfall will be very light at best. Winds will continue to be strong from the SW to W, and temperatures should be relatively steady near -4C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Approach lee and cross-loaded slopes with caution.
Be especially cautious as you transition into wind affected terrain.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.

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.