Avalanche Forecast

Archived

Dec 18th, 2025–Dec 19th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

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 60cm of storm snow has fallen. Strong to extreme winds have created widespread wind slabs at treeline and above. More snow and more wind is forecast. There is also a likelyhood of triggereing deeper weaknesses in the snowpack, thus creating very large avalanches.

Confidence

Low

Uncertainty is due to the limited number of field observations.

Avalanche Summary

On a road patrol on the Spray road revealed a widespread avlanche cycle has occured. One could see the winds continuing to blow had at treeline and above.

Snowpack Summary

This last storm has given us between 40-60cm of snow in the last 3 days. An additional 10-15cm of snow is forecast. Extensive wind slabs can be found in the Alpine and lee features at treeline. These wind slabs are likely to be reactive to skier traffic. A previous wind slab from Monday can be found down about 50-80cm and was sitting on a softer layer of decomposed crystals that should be investigated for its reactivity. The November crust is now down 100+cm. Any avalanche triggered in the upper snowpack has a strong likelyhood to step down to deeper instabilities. Now is a time to avoid exposure to avalanche terrain and give time for the snowpack to settle and stabilize.

Weather Summary

Another 10-15cm is forecast to fall by Friday mid-day alond with continued 75-100km/hr winds. The temperature in the alpine is forecast to cool off to -13.

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.