Avalanche Forecast

Archived

Jan 20th, 2024–Jan 22nd, 2024

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.

Cracking and whumpfing over the past few days indicates that the recently formed windslabs are able to be triggered by skiers/boarders. Keep an eye out for these problems as you transition into more treeline/Alpine areas.

Confidence

High

Avalanche Summary

A few new windslabs up to sz 2 were observed initiating from steep alpine terrain on N and E aspects.

Snowpack Summary

Warmer temps promoted settlement in the upper snowpack on Saturday. Windslabs 10-30cm thick are still common places along lee features (E and N aspects) in the alpine and treeline with cracking and whumpfing observed by forecasters while travelling in high treeline and alpine areas common. The windslabs are failing on weak facetted grains that formed during last weeks cold snow. Deeper in the snowpack the Dec 5th crust persists and has been making travel easier. In thinner areas, triggering the weak crystals under the crust is a real possibility so avoid steep thin and variable features in the terrain.

Weather Summary

Winds are forecast to become more light to moderate out of the SW on Sunday with trace amounts of new snow throughout the day. Temperatures will be around -3 during the middle part of the day so slightly cooler than Saturdays temps.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
Be carefull around freshly wind loaded features.
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.