Avalanche Forecast

Issued: Dec 10th, 2016 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Deep Persistent Slabs and Loose Dry.

tim haggarty, Parks Canada

Banff Yoho Kootenay.

The November 12 crust layer is losing strength, it should be carefully evaluated and consequences should be carefully considered before entering committing, or more aggressive terrain.

Summary

Weather Forecast

A short break from the extreme cold has brought a bit of precip and cloudy skies to southern areas over the weekend as the westerly flow won out for a while. Look for the north winds to return Monday dropping us even further into the deep freeze than we saw last week.

Snowpack Summary

Small wind slabs found in isolated alpine areas. 30-80 cm of settled snow over the November 12 crust. Stability tests on this crust are mixed, ranging from no results to easy results. This crust is more reactive in the Lake Louise area on southerly aspects above treeline. Rapid faceting and weakening of the snowpack with the cold temperatures.

Avalanche Summary

A few small loose dry avalanches observed in steep terrain as the surface snow facets and weakens. A few recent natural and skier triggered slab avalanches have been observed on southerly aspects in the alpine running on the November 12 crust.

Confidence

Due to the number and quality of field observations

Problems

Deep Persistent Slabs

The dominant issue in the snowpack is the November 12 crust (down 30-70 cm). This crust is evident throughout the region and has started to become reactive especially on South aspects just above tree line. Use caution with this developing layer.

Be alert to conditions that change with elevation.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Dry

As the surface snow rots with the cold temperatures, natural and human triggered sluffs are becoming more likely and have the ability to run quite far in steep terrain. Climbers and skiers in confined features such as gullies should beware.

Good group management is essential to manage current conditions safely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 11th, 2016 4:00PM