Avalanche Forecast

Issued: Dec 29th, 2017 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Our weak snowpack just had 20-30cm of snow put on top of it and another 10 is forecast for tonight.  Time to rein yourself in and allow the snowpack to settle to this new load.

Summary

Confidence

High -

Weather Forecast

Cold temps are expected to continue for a few more days until conditions begin to warm up late in the day on Sunday. Overnight on Friday we can expect another 5-10cm of snow to fall with winds pushing into the moderate range out of the north before they calm down during the day on Saturday. 

Avalanche Summary

A few slabs were observed failing with the recent snow on steeper unsupported terrain up to sz 1.5. These mainly occurred on southerly aspects. Of note some of the loose dry avalanches of late have gone very far and are sluffing fast entraining lots of snow as they travel down the slope. Ice climbers should pay particular attention.

Snowpack Summary

21cm storm snow overnight at Burstall with 30cm overnight at Aster lake. Storm snow tapers to 15cm at lower elevations. This new snow fell with light winds out of the north and as a result we are seeing some reverse loading in a few areas in the Alpine. Watch for new windslabs and storm slabs 20-30cm deep in alpine areas and at treeline in steeper terrain. These slabs will be slow to settle out with the cooler temps. Down 40-50cm in the snowpack is the December 15th surface hoar layer being found up to 2250m. A lack of a cohesive slab overlying this layer has prevented it being a problem but we can expect it to develop over the next few days as the snow settles. Pay attention where this layer is and isnt as you travel.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm slabs are building in Alpine terrain with the northern winds.  These slabs are overlying weak facets and windslabs in some areas.  Use caution as you transition into more alpine terrain.  Avoid steep and unsupported terrain.
Avoid freshly wind loaded features.Avoid travelling in areas that have been reverse loaded by winds.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

An icon showing Wind Slabs
Recently buried wind slabs are present in the Alpine on all aspects, and in isolated spots at Treeline. Steep and unsupported terrain are areas where triggering is more likely.
Avoid steep lee and cross-loaded slopesBe careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry
Occurring in steeper terrain but running into skiable lines. Ice climbers should be aware of this problem.
Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Dec 30th, 2017 2:00PM