Avalanche Forecast

Issued: Feb 13th, 2019 3:49PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

A good refresh out there, but watch for loose dry avalanches in the Alpine. These are running far and could be hazardous in the wrong terrain feature.

Summary

Confidence

High -

Weather Forecast

Thursday should be mostly clear with light winds and temperatures climbing to near -9Â by early afternoon. Friday and Saturday should be snowy with as much as 20cm on the way, but stay tuned for updates as we get closer to the expected precipitation event.

Avalanche Summary

Several naturally triggered loose dry avalanches occurred overnight with the new snowfall. These slides were found mostly in steep Alpine terrain on N and E aspects, ranging in size from 1.0 to 2.0 and notably running quite far down slope.

Snowpack Summary

10cm of new snow fell overnight, which is being re-distributed at upper elevations by light to moderate SW winds. Previously formed wind slabs are widespread on all aspects in the Alpine. These vary from being potentially reactive to skier traffic, to being completely "welded" in place. In other words, there is lots of variability out there. With the prolonged cold period the snowpack is facetting and loosing strength. However, in many areas, particularly deeper snowpack zones, the midpack is very dense and is providing lots of bridging strength over the weak basal facets. Though a full-depth avalanche is unlikely, if it does occur it will be catastrophic. Large triggers, such as a cornice failure, or triggering from a shallow snowpack area, are possible ways to wake up the deep persistent weak layer.

Problems

Wind Slabs

Wind slabs are widespread in the Alpine on all aspects. There is high amounts of variability in the sensitivity of these slabs.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded pockets while approaching and climbing ice routes.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Recent snow is contributing to a loose dry problem in steep terrain in the Alpine. These slides are running far down slope due to the stiffness of the layers below.

Avoid travelling under cliffs that are exposed to sluffing from above.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Deep Persistent Slabs

Thin areas should are where you could wake up the basal layers. Large and steep Alpine features are still a concern.

Carefully evaluate and use caution around thin snowpack areas.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Feb 14th, 2019 2:00PM