Archived

Avalanche Forecast

Feb 3rd, 2012–Feb 5th, 2012

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

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

Regions: Northwest Inland.

Warm alpine temperatures may result in unexpected large avalanches, especially on south-facing terrain.

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Saturday and Sunday: Dry or very light flurries, with alpine temperatures around -2C. Winds expected to be light southwesterly rising to moderate southeasterly. Monday: Clear with sunny spells. Temperatures below freezing at low elevations but alpine areas may see inversion conditions that will elevate temperatures to near zero.

Avalanche Summary

Small cornice releases that have so far not released slabs on slopes below were reported from Friday. A large nautral avalanche (size 3) was reported from the Hankin-Evelyn from last weekend on a NW aspect.

Snowpack Summary

I suspect pockets of wind slab behind ridges & ribs at alpine and treeline elevations. I also suspect storm slabs on steeper terrain, unsupported slopes, or convex rolls. Deeper in the snowpack is a layer of facets (sugary snow) which formed during the cold mid-January drought. The combination of newer, warmer, cohesive snow above a thin, weak, rotten snowpack is a bad combination.

Avalanche Problems

Cornices

Cornices are expected to become unstable with anticipated warm alpine temperatures.

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

Elevations: Alpine.

Likelihood: Likely

Expected Size: 2 - 6

Wind Slabs

Below ridge crests, behind terrain features and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 5

Storm Slabs

Facets down 40-60cm may take some time to gain strength. Watch steep slopes, convex rolls, and unsupported slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 4