Avalanche Forecast

Issued: Feb 22nd, 2012 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

Up to15cm of new snow fell at treeline, continuing to overload the Valentine's layers of surface hoar/facets/sun crust. Numerous slab avalanches observed at treeline and above in past 24 hours. Conservative route finding is advised. (JM).

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Cool temps with continued strong winds and very light precip.

Avalanche Summary

Numerous Na slabs up to size 2.0, mostly on N and E asp in ALP and TL.

Snowpack Summary

Variable Hn totals of 10 to 15cm at TL overnight. Total of 35 to 55cm overlies the Valentine's layers. Easy shears persist.

Problems

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 35 to 50cm.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Loose Dry

Loose unconsolidated surface snow is sluffing in steep terrain and continues to produce avalanches up to size 1.5. Ski cutting is triggering sluffs that could gain mass and/or trigger a slab below.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Cornices

Cornices have grown significantly over the last 24 hours. A couple of cornice failures today triggered size 2.0 avalanches on the slopes below. Beware of overhead hazard and stay well back of ridgecrests.

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

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 23rd, 2012 8:00AM