Avalanche Forecast

Moderate - Uncertainty is due to the limited number of field observations.

  

SUNDAY NIGHT: Cloudy with isolated flurries; 0-3 cm. / Moderate, southwest ridgetop wind / alpine low temperature -10 / Freezing level valley bottom.

MONDAY: Snow; 5-10 cm. / Moderate, southwest ridgetop wind / alpine high temperature -8 / Freezing level valley bottom.

TUESDAY: Snow; 15-25 cm. / Strong, south ridgetop wind / alpine high temperature -7 / Freezing level 300 m.

WEDNESDAY: Snow; 5-10 cm. / Strong, southwest ridgetop wind / alpine high temperature -6 / Freezing level 500 m.

A few very large, explosive triggered avalanches up to size 3 near Bell II this week provided evidence that a buried crust near the bottom of the snowpack combined with weak, sugary facets are reactive to large loads. This problematic snowpack structure may be more prevalent in the northern half of the region.

Cornice falls or smaller avalanches in motion may have the potential to step-down to these deeper layers, producing very large and destructive avalanches.

Data in this region is very sparse. Please submit your observations to the Mountain Information Network. 

  

Recent winds from a variety of directions have reverse loaded some slopes, creating wind slabs on typically windward features at treeline and above. 

The storm earlier in the week brought over a metre of snow accompanied by strong southwest winds to alpine elevations. Treeline elevations saw quite the mix of snow and rain depending on where the freezing level sat (mostly around 1200 m. during the storm). Below treeline the snowpack has likely refrozen into a firm crust. Cornices have likely grown large along ridgelines. 

The early December crust is now down 100 cm plus in the alpine and just below the surface at treeline. The early November crust is even deeper in the alpine and down 70-120 cm at treeline. Sugary facets near the bottom of the snowpack have produced large full depth avalanches pre-storm and during the storm. The extent of this problematic snowpack structure in the region is not well-known, but it likely exists in colder, shallower snowpack areas.

Snowpack depths are highly variable across aspects and elevations as a product of wind scouring, above-freezing temperatures, and rain. Snow has melted fast at lower elevations, and snowpack depths have seen rapid settlement.

• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
• Recent wind has varied in direction so watch for wind slabs on all aspects.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
• Avoid lee and cross-loaded terrain.
• Avoid shallow, rocky areas where the snowpack transitions from thick to thin.