Archived

Avalanche Forecast

Nov 24th, 2012–Nov 25th, 2012

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

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

Regions: Glacier.

Last weeks storms have improved conditions but there is little snow below 1500m. Recent reports and snowpack test results indicate a great deal of variability. Look for signs of instability and check the snowpack before committing to your line.

Weather Forecast

Scattered flurries ending this morning as the front continue to move southward. A clearing trend will begin this afternoon as a ridge starts to build. Expect light NW winds and increasing sun over the weekend.

Snowpack Summary

A cohesive storm slab is most reactive where it overlies the Nov 16 sun crust down ~30cm on steep solar aspects in the alpine. The Nov 6 crust is down 80-120cm, with facets forming around the crust. Test results are sudden planar, but hard.

Avalanche Summary

Recent avalanches have been triggered by strong S winds loading lee slopes. Yesterday there were 11 size 2-2.5 slab avalanches from steep north facing terrain. On Thurs there were 2 size 1.5 skier accidental avalanches triggered on the Nov 16 crust.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Storm Slabs

The storm snow is settling into a cohesive slab. It is most reactive on steep solar slopes in the alpine where it overlies a sun crust. Skiers have accidentally triggered avalanches on this layer that have run far and fast.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Assess start zones carefully and use safe travel techniques.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Wind Slabs

Strong southerly winds during last weeks storm transported snow, loading lee slopes and forming pockets of windslab. These windslabs may be buried by new snow.

Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2