Archived

Avalanche Forecast

Dec 5th, 2011–Dec 6th, 2011

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

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Banff Yoho Kootenay.

An inversion will leave by Tuesday morning. Light snow, seasonal temperatures, with strong NW alpine winds are forecast. Forecasters still have low confidence in the snowpack at higher elevations, especially in thinner areas East of the divide. SH

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

on Tuesday

Avalanche Problems

Deep Persistent Slabs

These slabs can be triggered from thin snowpack areas and propagate large distances to deeper areas. An example of this was a skier remote size 3 in the Lake Louise area on Sunday. The slab failed 140cm deep on weak basal facets and depth hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3

Wind Slabs

Deeper snowpack areas, mainly West of the divide, have quite a strong midpack, which was evident in field tests on Monday near treeline in the Little Yoho region. Thinner surface wind slabs, mainly on steep alpine slopes will be a concern.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 3