Archived

Avalanche Forecast

Dec 8th, 2022–Dec 9th, 2022

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

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: Glacier.

30-40cm of low-density storm snow is making for some quality skiing and riding!

Don't let the powdery conditions obscure your avalanche awareness. The persistent slab from Nov. 17th remains a major concern in isolated areas that have not seen previous heavy traffic. If you don't know the history of a steep open slope, leave it for another time.

Confidence

Moderate

Avalanche Summary

On Friday, a field team triggered a small storm slab on a small slope, on a SE aspect at treeline.

On Tuesday, a small natural avalanche cycle occurred in very steep, predominantly north-facing terrain in the Alpine. Cheops North 4 was directly observed (size 2, storm slab) stopping just short of the creek. Mt MacDonald had several size 1.5-2 storm slabs in the Highway Corridor, stopping at the top of the runout.

Snowpack Summary

Up to 40cm of new low-density storm snow buries the Dec 5th layer consisting of surface hoar and facets. Low-density storm slabs will likely be found in steep exposed start zones in the Alpine. The Nov 17th Surface Hoar is now buried 60-90cm below the surface and may become more reactive with the additional load.

Weather Summary

Up to 5cm of snow is forecast to fall overnight Thursday, bringing the snowfall totals to ~35cm since Monday.

Friday, we are expecting flurries, with light moderate SW winds, and alpine temperatures between -14*C and -12*C.

Into the weekend, we are expecting flurries, warming temps, and light winds.

Terrain and Travel Advice

Give the new snow several days to settle and stabilize before pushing into bigger terrain.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Loose avalanches may start small but they can grow and push you into dangerous terrain.

Avalanche Problems

Storm Slabs

30-40cm of low-density new snow accompanied by moderate to strong SW winds built fresh storm slabs in exposed start zones at higher elevations. The storm snow overlies the Dec 5th layer, which consists of preserved stellars and surface hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1.5 - 2.5

Persistent Slabs

The Nov 17 surface hoar is down 60-90cm and most prevalent around tree line. This layer of large surface hoar continues to give 'sudden' results in snowpack tests, and produce dramatic whumfs in previously untraveled open glades.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood: Possible

Expected Size: 1.5 - 3

Loose Dry

Approximately 35cm of dry, low-density snow has fallen this week. Expect fast sluffing in steep, confined terrain, potentially digging deeper into the facets and accumulating enough mass to bury a person.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2