Avalanche Forecast

Archived

Feb 3rd, 2023–Feb 5th, 2023

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

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.

Winds over the past 24hrs have been intense out of the west making windslabs more reactive in alpine areas and stripping windward slopes to bare rock.

Confidence

Moderate

Avalanche Summary

A few new sz 2 windslabs were observed along the smith dorrien on Wednesday. They looked to be on average 20cm thick. They were on all aspects but mainly initiating from thinner snowpack areas.

Snowpack Summary

Watch for windslabs in alpine areas as a result of strong winds over the past few days Where the snowpack is thin these are the places wherein a skier may trigger the weak basal facets. As the snowpack above the weaker base has become more cohesive the potential for wide propagation increases. This will be a common theme this winter and you should always be thinking about consequences of an avalanche. Wind slabs may also cause the weak base to fail. Its a tough snowpack this year and unfortunately, it isn't likely to change much this season.

Ice climbers in the Ghost and front ranges should watch for pockets of windslabs along routes that may be triggered.

Weather Summary

A few cms of snow is forecast along the Spray but accumulations are not expected to be significant. Temperatures will cool slightly with -6C at treeline elevations during the day with strong winds continuing out of the SW. There is a chance for some snow next week looking way off into the forecast.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.

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.