Archived

Avalanche Forecast

Dec 20th, 2013–Dec 21st, 2013

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

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

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.

Head's-up out there. The natural cycle is over, but human-triggered avalanches can still occur, especially in wind-effected areas.

Weather Forecast

Cloudy with trace amounts of snow are forecasted for the Pass today. Alpine temperatures should remain at -10*C or lower and winds in the light to moderate range from the SW. The weekend holds much of the same, with the next significant storm arriving on Monday.

Snowpack Summary

Up to 80cm of settled snow sits over surface hoar at lower elevations, facets and variable wind slabs at higher elevations. This interface is reactive, popping cleanly in snowpack tests. Strong winds have formed wind slabs and wind loaded pockets at treeline and above. Below this are 2 persistent weak layers sandwiched between facets.

Avalanche Summary

Natural avalanche activity has tapered off, but slabs now sit at depths easily triggered by light-loads, like humanoids. A number of field crews in the Pass yesterday backed off of larger slopes due to the ease in which the slabs were reacting down 70-80cm.

Confidence

Due to the number and quality of field observations

Avalanche Problems

Wind Slabs

Previous strong winds have created wind slabs in lee slopes at treeline and above. Watch for signs of weakness, like cracking and hollow-sounding snow.

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

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 2 - 3

Persistent Slabs

The recent snow has tightened into a slab. It sits on various weak crystals, like surface hoar and facets, that can be triggered by people. These avalanches may step down to deeper surface hoar layers, resulting in large avalanches.

Choose well supported terrain without convexities.Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 2 - 4