Avalanche Forecast

Issued: Mar 20th, 2012 4:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Snowfall amounts were less than expected, but forecasts are calling for 10cm of snow with strong W winds overnight. Wednesday afternoon could see some sunny periods with more snow coming Thursday. Cautious route finding is still advised.

Summary

Confidence

Fair - Due to limited field observations

Weather Forecast

The forecasted 20cm of snow failed to materialize on Tuesday, but perhaps the storm was delayed. Forecasts now say that 10cm of snow could fall overnight with continued strong westerly winds. A brief clearing trend is possible late Wednesday with more snow expected on Thursday.

Avalanche Summary

Nothing new was observed but observations were very limited.

Snowpack Summary

Up to 3cm of new snow at treeline overnight. Strong to extreme SW winds continue to form slabs in alpine and treeline areas in lee and crossloaded features. Extensive scouring has occurred.

Problems

Wind Slabs

Wind slabs up to 45cm thick are present in lee and crossloaded features. Avalanches starting in the upper snowpack will likely step down to one of the deeper layers. Recent avalanches have occurred on this layer. More loading is expected overnight.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Persistent Slabs

Surface hoar buried up to 150cm continues to be a major concern in the snowpack. A dense slab now sits on top of this layer. Avalanches in the upper snowpack will likely step down to this layer causing a destructive avalanche.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

2 - 6

Persistent Slabs

The March 11th temperature crust is buried an average of 50cm deep on solar aspects. The bond of the upper snowpack to this crust is highly variable and requires careful evaluation as you travel, especially during times of sunny or warm weather.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Cornices

Cornices have grown significantly in the alpine. Failures continue to occur and have triggered avalanches up to size 3 on the underlying slopes. Give cornices a wide berth and stay well back from corniced ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 6

Deep Persistent Slabs

The weak basal facets and depth hoar are still present. Large terrain features are areas of concern where a smaller slide could step down and trigger a very large avalanche with deep and wide propagation.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Mar 21st, 2012 9:00AM