Avalanche Forecast

Archived

Dec 17th, 2025–Dec 18th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural and human triggered avalanches likely.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

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

"CONTINUED HIGH AVALANCHE HAZARD"

Avoid all avalanche terrain. Up to 50cm of storm snow has fallen. Strong to extreme winds have created widespread wind slabs at treeline and above. There is also a strong likelyhood of triggereing deeper weaknesses in the snowpack, thus creating very large avalanches.

Confidence

Avalanche Summary

A natural avalanche cycle continues with this storm. Explosives control work on EEOR on Tuesday also produced several size 2 avalanches.

Snowpack Summary

Lots is going on in the snowpack. From Tuesday night to Wednesday afternoon, we received upwards of 40cm of storm snow. Associated with this storm were extreme west winds that have created widespread wind slabs at treeline and above. Additional snow and continued strong West winds will only create a thicker wind slab on the surface. We also have a another buried slab approximately 70-100cm down that is sitting on a softer layer of decomposed particles that was reactive to field tests 2 days ago. The November crust can now be found 100-120cm down. At the moment, if any of these weaknesses are triggered, there is a strong likelyhood that deeper instabilities will fail creating very large avalanches.

Weather Summary

We have received 40cm of storm snow. The extreme Westerly winds will diminish to strong on Wednesday evening and stay there for the entire day on Thurday. An additional 10cm of snow is expected by Thursday afternoon. The temperatures in the Alpine will stay between -7c and -15c.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Avoid areas with overhead hazard.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.

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.