Archived

Avalanche Forecast

Nov 25th, 2012–Nov 26th, 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.

Recent reports and snowpack test results indicate a lot of variability. Look for signs of instability and check the snowpack before committing to your line. Strong sun forecast for tomorrow may increase avalanche danger on solar aspects

Weather Forecast

Unsettled NW'ly flow is pushing across the area. Expect isolated flurries, sunny breaks, and light NW winds today. A ridge of high pressure is building tomorrow bringing mostly sunny skies, and light W-NW winds. High solar inputs are forecast.

Snowpack Summary

The storm slab is most reactive where it overlies a sun crust down ~30cm on steep solar aspects in the alpine. The Nov 6 crust is down 80-120cm with facets around the crust. Test results vary; from sudden planar to sudden collapse; and comp test easy to deep tap test hard.

Avalanche Summary

Recently, windloading is the trigger. Yesterday, 4 loose avalanches size 1.5-2 ran from steep terrain. On Thurs there were 2 size 1.5 skier accidental avalanches triggered on the Nov 16 crust. No avalanches have stepped down to the Nov 6 crust, yet.

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 propagated across terrain.

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 windslabs. These windslabs have been buried by new snow and may be difficult to recognize.

Avoid traveling on ledges and cliffs where small avalanches may have severe consequences.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2