Avalanche Forecast

Issued: Feb 28th, 2012 8:09AM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Choose terrain very carefully. Widespread cracking and whumpfing continue to occur and large avalanches have run in the past 3 days. This surface hoar problem will be with us for sometime.

Summary

Confidence

Good

Weather Forecast

Periods of snow developing midday on Wednesday with accumulations near 5cm. Another system late Thursday could bring up to 10cm. Moderate SW winds and cool temps.

Avalanche Summary

West of Super Slope one size 2.5 Na on S asp, 2500m ran 3/4 path. Northover Ridge 2 slides, one Nc on E asp 2700m and one on W asp 2600m. Both were size 2.5 with suspected failure plane of 120213 SH and SC. Evidence of previous cycle up to size 3.0 on all asp and all elevations.

Snowpack Summary

Widespread whumpfing and cracking continued today at TL and below. Widespread wind affect ALP. Numerous snow profiles today giving consistent results at CTE(11)(SC) down 30 to 60cm on 120213 SH. Midpack remains strong at all sites. Basal FC/DH have gained significant strength where Hs is over 180cm, but remains weak in shallow snowpack areas.

Problems

Persistent Slabs

The Valentine's surface hoar and sun crust continue to be problems with extensive avalanche activity in the past 3 days. The surface hoar is particularly touchy and is buried 40 to 80cm. Remote triggering, cracking and whumpfing occurred again today.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 6

Wind Slabs

Widespread wind slab formation has occurred in the alpine on lee and cross loaded features. It is likely that a failure in these wind slabs will step down and trigger the buried surface hoar or sun crust.

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

Elevations: Alpine.

Likelihood

Likely

Expected Size

1 - 6

Cornices

Cornices have grown significantly in the alpine. Failures continue to occur and have triggered avalanches up to size 2.5 on the underlying slopes. Give cornices a wide berth and stay well back from corniced ridgcrests.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 6

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

3 - 6

Valid until: Feb 29th, 2012 8:00AM