Avalanche Forecast

Issued: Mar 12th, 2013 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

We expect a natural avalanche cycle to start Wednesday and last for the next 48 hours. SH

Summary

Weather Forecast

West winds up to 110km and 30+cm of snow is forecast Wednesday at higher elevations, with highest amounts along and West of the divideÂ Freezing levels are expected to rise to 1900-2000m over the next 24hrs and remain there until Friday.Â We could see some rain in areas such as Field and Kootenay as freezing levels rise.

Snowpack Summary

A field trip to Kootenay found a well settled 2m snowpack at 2000m with the only compression results in the top 15cm of loose storm snow.Â 10cm supportive rain crust to 1800m in that area.Â This is a stark contrast to thinner snow pack areas which have storm slabs and wind slabs 30-40cm thick sitting over a mainly facetted snowpack.

Avalanche Summary

Ski cutting produced small but far running sloughs in steeper terrain today within the top 15-20cm of snow.Â The sloughs ran for approx. 200m.Â No other avalanches reported or observed.

Confidence

Forecast snowfall amounts are uncertain on Wednesday

Problems

Storm Slabs

New storm slabs will be sitting on a variety of surfaces, from colder powder snow or sun crust at higher elevations depending on aspect, to rain crust 1800m and below.

Good day to make conservative terrain choices.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Wind Slabs

Strong to extreme W winds will be developing wind slabs on lee aspects and will be sensitive to human triggering.

Avoid freshly wind loaded features.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Dry

At higher elevations, expect all gully features and exposed terrain to slough with the increased winds and new snow. Steep terrain below treeline may slough far and fast.

Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely - Certain

Expected Size

1 - 2

Valid until: Mar 13th, 2013 4:00PM