Archived

Avalanche Forecast

Feb 8th, 2017–Feb 9th, 2017

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Kananaskis.

A significant storm Thursday will push the hazard level back up. AVOID avalanche terrain at upper elevations. AVOID all overhead exposure while traveling Below Treeline.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

A warm and windy storm is approaching that will bring up to 25cm of new snow through the day. Gusty SW winds could reach 85km/h. Friday will see light flurries, before a clearing trend moves in for the weekend.

Avalanche Summary

Avalanche control on Mt Buller and the East End of Rundle (EEOR) had variable results, with some loose dry and slab avalanches up to size 2.5. The most significant avalanches occurred on EEOR where significant propagations occurred in the recently formed wind slabs. No new natural avalanches were observed today, but field teams did get some cracking along a ridge crest between 2450 and 2300m while ski cutting.

Snowpack Summary

Recent storm snow has settled to between 50 and 80cm, which overlies a hard slab in Alpine areas and some Treeline features. This snow has been redistributed by strong winds, and wind slabs are now dominant on all aspects at Treeline and above. These slabs seem most sensitive to human-triggering in the Treeline elevation band. Snowpack stability tests today indicate easy to moderate shears down 35 and 55cm. Concern remains for the potential of an avalanche initiated in the upper snowpack to step down to the weak basal layers causing a very large and destructive avalanche.

Avalanche Problems

Wind Slabs

Wind slabs already dominate the landscape at Treeline and above, and the forecasted storm for Thursday will add to this problem. A natural avalanche cycle is expected to start again on Thursday.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Very Likely

Expected Size: 2 - 3

Persistent Slabs

Triggering of these slabs from a thin weak area may cause an avalanche that involves the entire snowpack. With the recent additional snow load, triggering of these deeper layers is now more likely.

Minimize exposure during periods of heavy loading from new snow and wind.Be aware of thin areas that may propogate to deeper instabilites.Be aware of the potential for wide propagations due to the presence of hard windslabs.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4

Deep Persistent Slabs

The basal layers remain exceptionally weak. The potential for an avalanche initiated in the upper snowpack to step down to deep instability and cause a very large avalanche is a concern.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 2 - 4