Avalanche Forecast

Issued: Feb 10th, 2018 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

Natural avalanche activity has decreased over the past 24hrs. Human triggered avalanches are still a major concern

Summary

Confidence

High -

Weather Forecast

Winds are forecast to increase overnight into the strong range before easing on Sunday morning with the arrival of the cold front. Temperatures will begin to drop, and we may see a bit of snow as a weak upslope storm moves through the region.

Avalanche Summary

Avalanche control work today on Mt Buller produced slides up to sz 3 with fracture depths up to 1.5m. A few isolated natural avalanches up to sz 2 were observed in the north part of the forecast area but field observations in the southern areas were limited. Tell us what you are seeing at avalanche.safety@gov.ab.ca or via messenger on facebook.

Snowpack Summary

Winds and temperatures are causing the upper snowpack to settle. As it settles we are beginning to see natural avalanche activity begin to decrease but conditions are perfect for human triggerring. Wind slabs should be expected in the upper snowpack in the Alpine and isolated areas at treeline. These slabs are up to 40cm thick and on all aspects due to reverse loading. Any slab that initiates in the upper snowpack is likely to step down to any one of the lower wear layers. These layers include the Jan 18th and 6th surface hoar layers down being found below 2400m down around 1m+ and the Dec15th facet interface down 150cm being found all the way up and into the alpine. Stick to conservative terrain and minimize your exposure to overhead areas.

Problems

Wind Slabs

Found at treeline and above up to 50cm thick. They are being found on all aspects due to reverse loading patterns of recent winds.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Use caution in lee areas. Recent wind loading has created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 2.5

Persistent Slabs

Widepsread avalanche activity observed recently stepping down to the persistent deep layers such as Jan 6th Surface hoar and the Dec 15th Facet surface hoar interface. Any human triggerred slides will also likely step down to this interface

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3.5

Valid until: Feb 11th, 2018 2:00PM