Avalanche Forecast

Issued: Feb 23rd, 2012 9:18AM

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

mike.koppang, Alberta Parks

Kananaskis.

Up to 50cm of recent snow is now overlying the valentines day surface hoar and sun crust layer. A few skier accidental and skier remote avalanches have recently occurred indicating that this layer is sensitive to human triggering.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

LIght snowfalls to begin later in the day on Friday. Overnight, new snow and strong winds will likely push avalanche danger to high.

Avalanche Summary

Suprisingly little natural avalanche activity was observed on Thursday. Many slopes look extremely loaded and are simply waiting for the right trigger. Additional load from snowfall or winds will likely tips the scales and trigger a natural avalanche cycle.

Snowpack Summary

40-50cm of HST is now overlying the 0213SH/CR layer. This layer is still reactive to light loads such as a skier. Continue to get reports of shooting cracks from people travelling in open wind affected terrain.

Problems

Storm Slabs

Storm slabs have formed in open wind affected terrain that are reactive to light loads such as a skier. Thinner slabs will likely step down to the 0213 Valentines day layer triggerring an avalanche size 2 or greater.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Wind Slabs

Soft slabs are widespread in lee and cross-loaded terrain in alpine and treeline areas. Open areas below treeline have also been affected. These slabs are very sensitive to human triggering and are failing on the Valentine's layers down 40 to 50cm.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Cornices

A few recent cornice collapses have been observed throughout the forecast area. These collapses have triggered avalanches up to size 2.5 on the underlying slopes.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

2 - 5

Deep Persistent Slabs

Weak facets and depth hoar linger at the base of the snowpack. Thin steep areas are the most likely trigger points. This problem is still a low probability issue, but with high potential consequences.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Feb 25th, 2012 8:00AM