Avalanche Forecast

Issued: Jan 24th, 2012 4:00PM

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

Ian Jackson, Parks Canada

Banff Yoho Kootenay.

The forecasted precipitation will raise the avalanche danger on Wednesday, and may cause an avalanche cycle in the alpine and treeline. A ridge of high pressure will bring drier conditions and decrease the danger for Thursday and Friday.

Summary

Weather Forecast

Snowpack Summary

Avalanche Summary

Confidence

Forecast snowfall amounts are uncertain on Wednesday

Problems

Storm Slabs

Forecast of 10-20 cm with moderate to strong SW winds will create slabs in alpine and treeline. These will be touchy in open and wind effected areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Wind Slabs

At treeline 40-60 cm of settled storm snow sits overtop of the Jan 20 facet interface. In areas where the wind has created soft slabs this layer is reactive to skier triggering. Immediate lees of ridges above treeline are the areas of most concern.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

In most parts of the forecast area a settled midpack overrides a facetted base. This layer is becoming less likely to trigger, but it is still a good idea to use caution in thin areas where the likelihood of triggering these basal facets is highest.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Jan 25th, 2012 4:00PM