Avalanche Forecast

Archived

Dec 10th, 2025–Dec 11th, 2025

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

Crowsnest North, Crowsnest South.

Despite the recent warm and wet conditions at lower elevations, snow has likely been accumulating at higher elevations, accompanied by strong westerly winds.

Confidence

Moderate

Avalanche Summary

A few large (size 2 to 3) avalanches occurred on Tuesday. These avalanches were initiated by very large triggers, such as explosives or snowcats, and failed approximately 50 to 150 cm deep on the November crust described in the snowpack summary.

While natural avalanche activity is not expected on Thursday with cooling temperatures, rider-triggered avalanches may remain likely.

Snowpack Summary

Recent warm, wet, and windy conditions will result in heavy, wet snow or a surface crust, depending on elevation and region, by Thursday morning. Pockets of dry, wind-affected snow exist in alpine terrain.

A mid-November crust sits 50 to 100 cm deep. Below it, the snowpack contains multiple crusts, and in some areas, a weak, sugary facet layer exists near the ground.

Treeline snowpack depths range from roughly 50 to 100 cm, thinning quickly at lower elevations. In many areas, especially below treeline, slopes lack enough snow to cover ground roughness and produce avalanches.

Weather Summary

Wednesday Night
Cloudy. 25 to 35 mm of precipitation as snow or rain at treeline. 60 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1800 m.

Thursday
Cloudy. 3 cm of snow. 50 km/h west ridgetop wind. Treeline temperature -2 °C. Freezing level 1300 m.

Friday
Cloudy. 4 to 5 cm of snow. 40 km/h west ridgetop wind. Treeline temperature -5 °C.

Saturday
Mostly cloudy. 1 to 2 mm of precipitation as snow or rain at treeline. 50 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level 2000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
A hard crust on the snow surface will help strengthen the snowpack, but may cause tough travel conditions.

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.