Avalanche Forecast

Issued: Mar 4th, 2016 4:34PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Deep Persistent Slabs, Wind Slabs and Cornices.

Conrad Janzen, Parks Canada

Banff Yoho Kootenay.

High freezing levels combined with a weak mid-pack this means there is a lot of uncertainty in our snow pack over the weekend. Choose conservative route options until things improve.

Summary

Weather Forecast

Rising freezing levels (up to 2100m) with moderate West winds and small amounts of precipitation are forecast for Saturday and Sunday.

Snowpack Summary

15-20cm of snow over the past week at treeline. New sun crusts forming on solar aspects and moist snow at lower elevations. SW winds forming small wind slabs near ridge crests and in high alpine areas. In the main ranges a firm upper snow pack covers a weak mid-pack of facets and depth hoar which sits on a denser layer of facets near the ground.

Avalanche Summary

Some solar triggered sluffing out of steep rocky terrain and small cornice failures were observed in the Banff region on Friday. Several natural and skier triggered slabs on the weak mid pack facets have also occurred in the past several days in both Kananaskis Country and the Banff region showing the potential for avalanches on this weak layer.

Confidence

Freezing levels are uncertain on Saturday

Problems

Deep Persistent Slabs

The mid-pack facets remain weak, especially in thin or rocky areas. Avoid steep or unsupported terrain, and watch for signs of instability such as whumphing and cracking. This weakness is slowly healing but will be present for some time.

Be aware of thin areas that may propogate to deeper instabilites.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

SW winds have created small wind slabs in leeward ares near ridge crests. Use common sense to avoid these places, and pay attention to the snow surface conditions while touring - you can usually detect wind slabs easily.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

Warm temperatures over the weekend combined with moderate west winds and some light precipitation could result in increased cornice failures. Minimize your exposure to cornices and the slopes below them as the day heats up.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 5th, 2016 4:00PM