Archived

Avalanche Forecast

Dec 7th, 2022–Dec 8th, 2022

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

2: Moderate

The avalanche danger rating in the alpine will be moderate

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, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Little Yoho, Sunshine, West Side 93N.

The basal facets aren't getting any smaller, and we have a more traditional snowpack than we have had in the past couple of winters. There are some fresh wind slabs, as well as weak facets near the ground. Treat any slope that has a wind slab overlying facets or crusts with caution as the potential for human triggering is higher.

Confidence

Low

Avalanche Summary

One size 1.5 to 2 today in the Healy Creek area, failing on facets today. Lots of whumpfing in the Sunshine area overall, mainly on the facets. No other observations.

Snowpack Summary

5-25cm of snow and wind over the last few days has formed fresh wind slabs at higher elevations.

Here is an image of the typical snowpack in the Rockies; 81 cm snowpack at treeline at Crowfoot Glades. A few cm of low-density new snow on the surface, then about a 20-30 cm slab overlying the Nov 22 interface, below which facets and weak snow grains exist to ground. This snowpack is generally weak and will not handle much extra load.

Weather Summary

SW winds of 40-60 kph are expected overnight into Friday. Expected temperatures are -15C at ridgetop. On Friday, 20-40 kph winds are expected (some models showing higher values) with flurries and ridgetop temperatures ranging from -10C to -15C.

Avalanche Problems

Persistent Slabs

A 20-60 cm slab sits over a persistent weak layer of basal facets, buried sun crusts, or isolated pockets of surface hoar. This layer has considerable uncertainty associated with it making it hard to forecast, and will be around for some time to come.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2.5

Wind Slabs

5-25 cm of snow has fallen over the past few days and now will be blown into soft wind slabs. Watch for these on the immediate leeward side of ridges.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 1.5

Loose Dry

There is still a fair amount of loose snow sitting around on cliffs and ledges. If winds stay elevated on Friday, an avalanche will not be large but could collect in gullies with enough volume to knock a person over.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible - Likely

Expected Size: 1 - 1.5