Avalanche Forecast

Issued: Feb 8th, 2018 3:00PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is high. Known problems include Storm Slabs, Wind Slabs and Persistent Slabs.

Alberta Parks michael.olsthoorn, Alberta Parks

"AVOID TRAVELLING IN, OR NEAR AVALANCHE TERRAIN"Special Public Avalanche Bulletin in effect:https://www.albertaparks.ca/parks/kananaskis/kananaskis-country/advisories-public-safety/advisory/#32996

Summary

Confidence

-

Weather Forecast

The storm from Wednesday until Thursday afternoon has deposited 30cm of snow at valley bottom with wind at all elevations.  This amount will likely increase slightly as the storm passes and the various weather models show continued wind into the evening.For Friday and the weekend, expect a mix of sun and clouds, and alpine temperatures around -15c.

Avalanche Summary

LARGE SCALE AVALANCHES EXPECTEDThis morning, on the Spray highway, it was snowing hard and the skies were obscured to observe any avalanche activity.  Large scale avalanches have been observed everyday this week and as late as yesterday(Wednesday). This rapid loading will likely have started a significant avalanche cycle and we are expecting these slides to run full path right down to valley bottom. These slides are also expected to go further and larger than previously seen.

Snowpack Summary

The snowpack has been rapidly loaded with 30-40cm of snow.  This is dramatically compounded by the fact that wind was associated with this storm which translates to wind loaded pockets in the alpine and in lee features.  Expect this additional load of new snow and wind deposited snow to have a great effect on the buried weak layers.  This will mean that whatever slope that has not slid, will be primed for HUMAN TRIGGERING and will likely step down to a deeper layer creating large avalanches.  These weak layers that we have been talking about for a long time are primed for avalanching and are found at the following depths:-Jan 18 surface hoar approx. 130cm down from the surface-January 6 surface hoar approx. 150cm down from the surface and-December 15 interface approx 180cm down from the surface-November crusts approx.  210cm down from the surface

Problems

Storm Slabs

An icon showing Storm Slabs
These can be quite thick due to the new snow and wind.
If triggered the storm slabs may step down to deeper layers resulting in large avalanches.Select routes that do not travel in or under avalanche terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely - Certain

Expected Size

1.5 - 3

Wind Slabs

An icon showing Wind Slabs
Present on all aspects. There are actually several slabs that are being lumped together with this problem. In the alpine some are buried and may need a quick dig to find.
Select routes that do not travel in or under avalanche terrain.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely - Certain

Expected Size

2 - 3.5

Persistent Slabs

An icon showing Persistent Slabs
These layers  are up to 200cm down.
Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 3.5

Valid until: Feb 9th, 2018 2:00PM