Avalanche Forecast

Archived

Dec 8th, 2024–Dec 9th, 2024

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.

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.

New snow has refreshed the region, but unfortunately extreme winds have created extensive new wind slabs. These slabs will be sensitive to human triggering. Look to sheltered areas for better quality turns.

Confidence

Moderate

Avalanche Summary

No new avalanches were observed or reported today.

Snowpack Summary

New snow amounts were highly variable though the region in the past 24 hours: 3-10cm at valley bottom, an average of 20cm at 2400m, with one station reporting 30cm. Western regions received significantly more than the eastern side of the forecast area. Strong to extreme winds have stripped windward and ridge features down to bare scree, while loading lee and cross-loaded terrain. Expect to find freshly formed wind slabs at treeline and above. The recently buried Dec 7 crust layer seems isolated through the terrain, found mostly on solar aspects. This layer hasn't yet produced any new avalanche activity, but will be one to watch. Snowpack depths at treeline average 70cm, which is on the lower end of average for this time of year. Generally the snowpack is weak and facetted. The Nov and Oct rain crusts are steadily deteriorating into layers of facets.

Weather Summary

Sunday night will produce our coldest temperature in a while with the mercury dropping to near -18C! Monday should be mainly sunny with light to moderate NW winds and a high temp near -8C. No new snow is expected for Monday or Tuesday.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid freshly wind-loaded terrain features.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
Use conservative route selection and resist venturing into complex terrain.
Avoid steep terrain that is rocky and thin.

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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.