Avalanche Forecast

Issued: Feb 11th, 2013 4:00PM

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

mike eder, Parks Canada

Jasper.

Tuesday's avalanche danger will increase if the forecasted frontal passage comes in Monday night instead of Tuesday night.

Summary

Weather Forecast

Up to 20cm of snow could fall as a front passes through the area beginning later in the day on Tuesday and continuing through to Wednesday mid day. Temperatures will drop by a few degrees overnight as the front passes and a trailing cold front settles into the area.

Snowpack Summary

Hard windslab is bridging the weak basal facets above treeline.Â Field tests in the alpine on a SE windloaded terrain feature produced easy results on a buried surface hoar layer directly below the hardslab. This confirms that there are several weak layers below that the avalanche can slide on.Â Below treeline, the mid-pack is weak.

Avalanche Summary

No new avalanches were observed today.

Confidence

Forecast snowfall amounts are uncertain on Tuesday

Problems

Wind Slabs

Up to 10cm of snow from recent flurries has been redistributed by moderate NW winds onto the Southeast aspect of terrain features. This soft slab could knock a person over in steeper terrain.

Be careful with wind loaded pockets while approaching and climbing ice routes.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

The hard windslabs that dominate the alpine snowpack have been unreactive lately. It still may be possible to trigger an avalanche on steep unsupported terrain from thin areas and the edges of these slabs.

Be aware of thin areas that may propogate to deeper instabilites.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

1 - 3

Valid until: Feb 12th, 2013 4:00PM