Archived

Avalanche Forecast

Mar 6th, 2012–Mar 7th, 2012

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

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

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.

Clearing skies and avalanche control work at the end of the storm highlight some impressive avalanche events. Deep fracture lines, long run outs and widespread propagation within soft slabs in the alpine continue to highlight dangerous conditions/BD

Confidence

Good

Weather Forecast

Snowfall tapering off but NW winds increasing to EXTREME values over next 24 hours.

Avalanche Summary

Numerous natural soft slab avalanches to Size 3.5 over past 24 hours. Typical fracture lines are 75 to 150 cm deep. Avalanche control via helicopter bombing produced numerous Size 2-3 slides with wide propagation and long run outs up to 1000 meters. One natural Size 3 slide on Buller Mtn reached the road with deposits up to 1.5meters deep.

Snowpack Summary

22cm additional snowfall by Tuesday AM when the storm ended. Total snowfall over the past 36 hours is approx 60 in valley bottom with as much as one meter at treeline. Storm snow in wind loaded areas will easily exceed 1 meter depth.

Avalanche Problems

Wind Slabs

Winds have formed hard and soft slabs at all elevations on lee and cross loaded features. A failure in these slabs will likely step down and trigger the surface hoar or the basal facets. Avalanches are occurring on this layer.

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

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 6

Persistent Slabs

The Valentine's surface hoar and sun crust continue to be a problem The surface hoar is particularly touchy and is now buried over 125 cm's at treeline and above. Remote triggering, cracking and whumpfing are occurring.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Very Likely

Expected Size: 1 - 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. Avalanches are stepping down to this weakness.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 3 - 6

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: Likely

Expected Size: 2 - 6