Avalanche Forecast

Issued: Mar 13th, 2017 3:44PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

An approaching storm may bump the hazard level up to HIGH. Pay attention to localized conditions. Loose wet avalanches are also possible if warm daytime temperatures and/or intense solar radiation occur.

Summary

Confidence

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

Weather Forecast

Tuesday will see the start of a warm and wet storm that could bring as much as 20cm by late Wednesday. Winds will be strong from the SW and freezing levels could reach 2200 to 2300m.

Avalanche Summary

A few naturally triggered size 2 avalanches were observed today in the Alpine on S, E and N aspects. Some of these were cornice triggered. Over the weekend a couple of very large avalanches occurred (up to size 3.5) which ran full-path and also destroyed areas of mature timber. These larger slides have been stepping down to the basal weak layers.

Snowpack Summary

Up to 5cm of new snow fell in the past 24hrs. Wind slabs are present at Treeline and above on all aspects and seem sensitive to human-triggering. Forecasters observed isolated cracking in steep and unsupported convex roles at Treeline today. The biggest concern is the weak basal layers that exist throughout the region. These layers just simply cannot be trusted and all larger features should just be avoided until we go through a few solid melt freeze cycles. Thin melt freeze crusts are being found on solar aspects up to 2400m.

Problems

Wind Slabs

Wind slabs are widespread in Alpine and Treeline terrain on all aspects, but expect deeper slabs on lee and cross-loaded features. An approaching storm may add significantly to this problem.

Caution in lee and cross-loaded terrain near ridge crests.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Deep Persistent Slabs

Any avalanche initiated in the upper snowpack could step down to the weak basal layers resulting in a very large avalanche. Recent events indicate that this is very possible (see avalanche discussion).

Be aware of the potential for wide propagations.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Cornices

Cornice collapses are triggering slabs up to size 3.5 on underlying slopes waking up the basal layers.

Extra caution needed around cornices with current conditions.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

2 - 4

Valid until: Mar 14th, 2017 2:00PM