Avalanche Forecast

Issued: Dec 18th, 2017 4:41PM

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

ian jackson, Parks Canada

Banff Yoho Kootenay.

New snow on Sunday night has created some soft slabs. These are mostly soft and predictable, but watch out for local wind effect and deeper storm snow amounts. Ice climbers should be wary of sluffing in steep terrain!

Summary

Weather Forecast

5-10 cm is forecast to fall Tuesday afternoon, and then temperatures will drop with clearing skies on Wed and Thursday and lows into the -20's. Expect to see the winds switch from MW to SE on Tuesday morning and increase to moderate SE in the alpine.

Snowpack Summary

10-30 cm of soft storm snow now covers a mix of sun crust, facets, wind slab and surface hoar depending on the aspect and elevation. We are calling this layer the Dec. 15th layer, and it will become reactive as we get more load on it. The lower snowpack is generally facetted with no shears present.

Avalanche Summary

Several small size 1-1.5 natural and skiier controlled avalanches involving last nights storm snow were observed mostly in the Lake Louise Ski Hill area and backcountry. Additionally, there were a few isolated small avalanches around Sunshine and Bow Summit areas where they received less snow.

Confidence

Problems

Storm Slabs

10-30 cms of new snow from Sunday night has formed soft slabs that are reactive in steep alpine lee areas. Touchiness will depend locally on snow amounts and wind speeds.

Use caution in lee areas. Recent wind loading has created fresh slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 19th, 2017 4:00PM