Archived

Avalanche Forecast

Mar 12th, 2012–Mar 13th, 2012

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

4: High

The avalanche danger rating below treeline will be high

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

4: High

The avalanche danger rating at treeline will be high

Below Treeline

3: Considerable

The avalanche danger rating below treeline will be considerable

Regions: Glacier.

The snowpack is prime for triggering. 60cm of snow this weekend brought it to the tipping point, overloading a series of weak layers and resulting in a large avalanche cycle. Another storm is forecast for today. Expect widespread avalanches. DM

Avalanche Problems

Persistent Slabs

Weak layers from Feb (combinations of surface hoar, sun crusts and/or facets) continue to produce impressively large avalanches. These layers are down 1.5 to 2m and may be triggered by skiers, loading by wind or cornice fall, or stepping down.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 3 - 4

Storm Slabs

Up to 60cm of snow fell over the weekend, with temps at treeline rising to just above freezing and moist snow to 1600m. This cohesive slab is reactive and may step down to deeper persistent layers resulting in very large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 2 - 3

Wind Slabs

Southerly winds are transporting snow, loading slopes and forming windslabs on exposed slopes at treeline and above. Large avalanches occurred this weekend on lee slopes. These windslabs overlie lower density snow and may be triggered by skiers.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 3