Avalanche Forecast

Issued: Dec 20th, 2017 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 Loose Dry.

snow safety, Parks Canada

Banff Yoho Kootenay.

Dress warm and be careful for windslabs near ridge-crests, and loose snow from steep rocky features. Ice climbers may experience loose snow pour-overs as things facet out.

Summary

Weather Forecast

Some more snow is forecast for Thursday. Amounts possibly in the 5cm range. Then it is expected to get cold. As the Arctic air pushes in wind chills are expected to be fairly high. Dress warm.

Snowpack Summary

10-30 cm of soft snow now covers the Dec 15 persistent weak layer of surface hoar, sun crust or facets (depending on location). Multidirectional winds have created windslabs near ridge-crests on many aspects. Plumes were noted in Lake Louise today.

Avalanche Summary

One shallow slab avalanche was noted behind the Hwy 1/Hwy 93N intersection.

Confidence

Problems

Wind Slabs

Strong NE winds will easily transport the 25 cm of recent snow into windslabs on S and W aspects (backwards from usual). Avoid freshly wind loaded rolls and slopes and study the snowpack distribution from this upslope storm.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

Climbers in steep gullies be prepared for spindrift and loose snow running down the climb. Put in lots of ice screws. Any avalanches will likely be small, but could knock you off your feet.

Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 1

Valid until: Dec 21st, 2017 4:00PM