Archived

Avalanche Forecast

Nov 29th, 2014–Nov 30th, 2014

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

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

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: Banff Yoho Kootenay.

Natural activity has slowed down after the big storm, but conditions are prime for human triggering due to the deeper weak layers. Choose very conservative terrain. SH

Weather Forecast

Cold and clear on Sunday with temperatures in the mid minus 20's. We will see a slight warming trend through the forecast period and alpine winds shifting to a W/NW flow.

Snowpack Summary

Storm snow amounts over the last few days: 40cm in the Kootenay region, 50cm in the Lake Louise area, and 60 cm at Sunshine. 2 layers of concern, the Nov. 6th rain crust/facets 20-30cm above the ground, and the Nov 24th facet layer 25-50 cm above the ground. The new load of storm snow is overloading these layers.

Avalanche Summary

A natural cycle to sz. 3 on all aspects at treeline and above occurred during the storm. Explosive control at Sunshine and Lake Louise ski areas have been producing avalanches up to size 2.5. There is also extensive whumpfing at all elevations and aspects. A notable size 2.5 and size 2 were likely remote triggered in West Bowl in Lake Louise today.

Confidence

Due to the number of field observations on Saturday

Avalanche Problems

Persistent Slabs

The new snow load has overloaded the weaker rain crust/facet layers below. Cold temperatures have helped tighten the snowpack, but we will see this condition persist. Below treeline features are less reactive but avoid steep, open features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3

Wind Slabs

Upper elevation winds during the storm have formed wind slabs which can step down to deeper layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 2