Avalanche Forecast

Archived

Jan 17th, 2024–Jan 18th, 2024

Alpine

Natural avalanches unlikely, human triggered possible.

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 possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

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

Cooler temps on Thursday to start the day with a gradual warming. Small inputs of snow are incrementally increasing the windslab thickness in alpine and treeline terrain so use caution as you transition into these areas.

Confidence

High

Avalanche Summary

No new avalanches were observed on Wednesday but observations were limited.

Snowpack Summary

Of the snow that was forecast, only 5-8cm fell over the past 24hrs with generally very little wind except in the alpine terrain. This new snow is overlying the weak facetted snow from last week as well as windslabs in alpine terrain up to 30cm thick along ridgelines and in gullied features. The windslabs have a distinct cakey feel along the ridgelines as you transition into more open areas. Deeper in the snowpack the Dec 5th crust is being found up to 2350m with weak facets and depth hoar below this layer. Thin areas are places a skier may be able to trigger a failure in these basal facets that can propagate across a feature. Continue to check the depth of the snow as you travel feeling into the snowpack for the hard over soft feeling (Crust over basal facets). In below treeline areas, the snowpack is generally shallow with lots of logs and alders present.

Weather Summary

The deep freeze returns? Thursday is looking to be around -30 to start the day then warming up into the -15 range during the day. Winds will be light but they are NE'ly again meaning the cold air is here once again. A few more cm's of snow may fall overnight but not a significant amount.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Recent wind has varied in direction so watch for wind slabs on all aspects.

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.