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Avalanche Canada michael.olsthoorn, Avalanche Canada

Kananaskis Country Avalanche Forecast

Mar 6th, 2019 3:00PM

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

We are in a pattern of change with the warming temperatures and Spring like weather.  Limit your exposure when the solar radiation is strong.

Summary

Confidence

High -

Weather Forecast

Thursday is to bring a mix of sun and cloud with a chance of light flurries in the afternoon.  The morning will start at around -17c and warm up to -7c.  Winds are expected to be moderate from the SW.

Avalanche Summary

One size 2 slab avalanche on a south aspect on Mt. Birdwood occured in the last 36 hours.  This slab was 20-40cm thick.  Numerous other loose dry and thin slab avalanches were observed in the alpine running into treeline from East to South aspects.

Snowpack Summary

Wind slabs are in abundance in the Alpine.  As you descend to tree line, these slabs seem to quickly disappear, likely due to the persistent facetting.  The bridging strength of the midpack  that we have been observing all winter at tree line and below has disappeared. Overall the snowpack is very weak and it is possible that loose snow facet avalanches could occur at any elevation, triggered by solar input, cornice failures, loose rocks or a skier/rider. These slides have the potential to run far and could be problematic in gullies and similar terrain traps. At low elevations expect ski penetration to ground if you leave an established track.  The solar radiation is starting to have an effect on slopes that are facing the sun. 

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely - Possible

Expected Size

1 - 2
A variety of wind slabs can be found through the Alpine. These sit on a layer of facets and could be sensitive to triggering in steeper terrain.
Caution in lee and cross-loaded terrain near ridge crests.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Unlikely

Expected Size

1.5 - 3
We are thinking this layer is becoming more reactive over time. As the slabs facet/weaken, the bridging effect will become less reliable. It is also possible that this layer will "wake up" as the days become warmer and the solar input increases.
Be aware of thin areas that may propogate to deeper instabilites.Be aware of the potential for full depth avalanches due to deeply buried weak layers.Be aware of the potential for wide propagations due to the presence of hard windslabs.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Loose Dry

An icon showing Loose Dry

Likelihood

Likely - Possible

Expected Size

1 - 2
Mostly a problem in steep terrain, but we are starting to see some solar triggered slides as well.
Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Mar 7th, 2019 2:00PM