Avalanche Forecast

Issued: Mar 23rd, 2012 4:00PM

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

Tim Haggarty, Parks Canada

Waterton Lakes.

Following a few days of snowfall forecasts call for intense warming on Sun and Mon. The recently formed windslabs and storm slabs could become sensitive to triggering if this occurs. Large events may occur if small events trigger deeper layers.

Summary

Problems

Wind Slabs

Winds form varying directions have been active recently creating soft slabs in areas you would not normally expect to find them. Feel for these slabs in open areas with your poles and avoid large or planar slopes where they may be present.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Storm Slabs

Below 1900m the recent snow is sitting on a rain crust: the bond here may deteriorate especially with warming. At upper elevations the recent snow is less distinct but layers of different densities are present: dig down to confirm the bond.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

The warming March 10 created a thick crust in most areas to treeline and to ridgelines on solar aspects now down 1m+. This crust is showing signs of breaking down and as the slab consolidates above this layer it could become reactive to heavy loads.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Mar 26th, 2012 4:00PM