Archived

Avalanche Forecast

Dec 4th, 2013–Dec 5th, 2013

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

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

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Glacier.

Touchy slabs are being triggered by skiers. Don't let the blue skies influence your decision to attack the big lines.

Weather Forecast

The high pressure ridge will hold strong over the Columbias for the next few days. Alpine highs will slowly sink to -20*C or lower by the weekend, with light northerly ridge-top winds, and no snow in the near future.

Snowpack Summary

30-40 cm of storm snow is over the November 28 surface hoar/crust interface. The November 12 surface hoar layer is down 60-110cm.

Avalanche Summary

A large size 3 was observed off a N aspect on Cheops, as well as several size 2 avalanches from SSE aspects in 8812 Bowl. Several size 2 to 2.5 avalanches throughout the highway corridor yesterday, including a size 2.5 from Moccasin Flats that showed good propagation. All appeared to be 30-40cm deep, likely on the Nov 28 surface hoar/crust.

Confidence

Due to the number and quality of field observations

Avalanche Problems

Wind Slabs

Surface slabs have stiffened with wind-effect and cooler temperatures. These slabs appear to be touchy and are well within the range of skier-triggering. Northerly winds have reverse-loaded alpine and tree-line lee areas.

Be cautious as you transition into wind affected terrain.Use caution in lee areas in the alpine. Recent wind loading have created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

The surface hoar buried earlier this month is slowly decomposing, but could be reawakened by surface slabs overloading it.

Be aware of thin areas that may propogate to deeper instabilites.Dig down to find and test weak layers before committing to a line.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 2 - 3