Avalanche Forecast

Issued: Dec 7th, 2015 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Storm Slabs.

ian jackson, Parks Canada

Banff Yoho Kootenay.

Recent snow on the Icefields Parkway is making for excellent skiing! We are expecting a juicy storm starting Tuesday around noon which will raise the danger. If it doesn't materialize as forecast, the danger rating may be lower.

Summary

Weather Forecast

The next storm is forecast to bring 15 - 30 cm's starting Tuesday around noon followed by a smaller system bringing 5-10 cm's starting on Wednesday at noon with the highest amounts near Bow Summit. Moderate to strong W winds will continue in the alpine and freezing levels peak Tuesday around 1700m with the influence of the south westerly flow.

Snowpack Summary

The Dec 3rd interface is now buried by 30-50 cm of storm snow and is a layer to watch right now. This interface consists of facets and large surface hoar below 2000m, wind effect in the alpine, and suncrusts on steep S and SW aspects. Moderate S and SW winds are building soft slabs in the lee of alpine features. The lower snowpack is well settled.

Avalanche Summary

Small windslabs local to ridgecrests are reactive to skier traffic in the alpine and at treeline. Some cracking observed in a steep below treeline glade today where the Dec. 3rd surface hoar was present. Limited observations in the alpine due to poor visibility.

Confidence

Timing, track, or intensity of incoming weather system is uncertain

Problems

Wind Slabs

15-40 cms of storm snow in the alpine and at treeline is being blown by moderate to strong S/ SW winds and forming windslabs in immediate lees of prominent features and ridgelines.

Use caution in lee areas. Recent wind loading has created wind slabs.Be cautious as you transition into wind affected terrain.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Storm Slabs

15 - 45 cm's of new snow is slowly settling into a cohesive slab. This slab will be most reactive in deeper snowpack areas where there is more than 30 cm's of new snow and below 2000m where it overlies the Dec. 3rd surface hoar or facets.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 8th, 2015 4:00PM