Avalanche Forecast

Archived

Dec 17th, 2024–Dec 18th, 2024

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

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.

The AVALANCHE HAZARD is increasing with the incoming storm. Approach all avalanche terrain with caution. Take the time to evaluate the effects of the incoming storm.

Confidence

Moderate

Avalanche Summary

No new avalanches have been observed on Tuesday. Expect some avalanche activity on Wednesday with the incoming storm.

Snowpack Summary

Watch for new wind slabs in all open areas that will be sensitive to skier traffic. The more snow and wind that arrives, the higher the avalanche hazard will be. It is possible for localized areas to jump to HIGH Hazard if we get 30cm or more with the strong winds. In either case, any snow load on our weak snowpack will likely fail on the October crust/facet combo(which is close to the ground). Approach all open areas with caution and take the time to evaluate how much snow has fallen and how strong the effects of the wind have been.

Weather Summary

All weather models are calling for snow Tuesday night and on Wednesday but the amounts vary from 10-30cm. All of the models are calling for strong SW winds along with an alpine temperature of -5c.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Storm slab size and sensitivity to triggering will likely increase through the day.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Don't let storm day fever lure you into consequential terrain.

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.