Avalanche Forecast

Issued: Dec 11th, 2016 4:31PM

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

conrad janzen, Parks Canada

Banff Yoho Kootenay.

We have moved to Low hazard but it is important to remember that the definition of Low includes small avalanches in isolated or extreme terrain. Watch for sluffing to increase as the snowpack weakens and facets.

Summary

Weather Forecast

Moderate northwest winds return on Monday dropping us back into the deep freeze. Temperatures will be slightly warmer than last week but dress warm. Clear skies and sunshine are forecast for the next several days.

Snowpack Summary

A few cm's of new snow sits over small wind slabs in alpine areas near ridge crests, and weak faceted snow in sheltered 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. Rapid faceting and weakening of the entire snowpack with the cold temperatures.

Avalanche Summary

Small loose dry skier triggered avalanches in steep terrain have been reported in several locations over the past few days as the surface snow facets and weakens. Lake Louise had a couple small soft slabs that they were able to trigger with explosives in steep N facing rocky terrain. No other avalanches observed or reported in the past 4 days.

Confidence

Due to the number of field observations

Problems

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 be wary of this.

Be aware of party members below you that may be exposed to your sluffs.On steep slopes, pull over periodically or cut into a new line to manage sluffing.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

The November 12 crust (down 30-80 cm) is evident throughout the region and has been reactive especially on South aspects just above tree line. Use caution with this layer on large slopes.

Be alert to conditions that change with elevation.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Dec 12th, 2016 4:00PM