Avalanche Forecast

Issued: Mar 12th, 2012 8:26AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Persistent Slabs, Storm Slabs and Wind Slabs.

Grant Statham, Parks Canada

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

Summary

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

Valid until: Mar 13th, 2012 9:00AM