Archived

Avalanche Forecast

Dec 23rd, 2011–Dec 24th, 2011

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

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

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: Glacier.

The forecast is for a warm front to bring moderate precipitation Friday afternoon into Saturday. Winds will remain at transporting range from the SW. Dec 11 Surface Hoar may become touchy again!Fidelity: -11/-4 HN24 1 HS 205 Macdonald winds S 35

Avalanche Problems

Persistent Slabs

A layer of surface hoar buried on Dec. 11 is overlaid by 50cm of low density snow. This is becoming a persistent weak layer. This problem has caused several recent skier involvements. It may still be touchy in areas that have not yet avalanched.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3

Wind Slabs

Wind slabs can be expected at ridge tops. The concern is for uneven snow distribution and slabs propagating from thin snowpack areas. Wind slabs formed early in the storm may be buried by 20cm of new snow.

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

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1 - 3

Deep Persistent Slabs

A weak basal crust is present in the alpine and was responsible for large avalanches. The deep layers are generally unreactive but may be triggered from thin snowpack areas. Glide cracks are forming at all elevations. One failed at 1100m Dec 22.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Unlikely

Expected Size: 3 - 4