Avalanche Forecast

Issued: Nov 13th, 2015 4:00PM

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

snow safety, Parks Canada

Banff Yoho Kootenay.

Storm slabs are rapidly loading and failing with the new snow, increased winds, and warm temperatures.

Summary

Weather Forecast

Strong to extreme SW winds are expected to last into Saturday morning and up to 10cm overnight and throughout the day.Â Winds should diminish by the afternoon Saturday with freezing levels to 1700m.Â Another weaker system will bring some light snow amounts Saturday night into Sunday .Â Monday will see lowered freezing levels and clearer weather.

Snowpack Summary

30-35cm at treeline over the last 24 hours in the Sunshine, Lake Louise and Bow summit areas , and an average 65-80cm snowpack at treelineÂ Warm temperatures have caused quick settlement of the storm snow.Â There is a layer of surface hoar and suncrust that exists in many areas which is acting as a sliding surface for the new snow.

Avalanche Summary

Ski hills were reporting conditions becoming "very touchy" Friday afternoon at treeline due to increased winds.Â Slides to size 2 (40cm deep, 50m wide) were being triggered on a mixture of sun crust, surface hoar, and the ground.Â Limited backcountry observations today due to visibility, but an avalanche cycle is surely occurring up high!

Confidence

Due to the number of field observations on Friday

Problems

Storm Slabs

The new snow will be warm, heavy and wind driven: perfect for slab development. New slabs will likely bond poorly to the weak dry snowpack that currently exists in most areas and the crusts and surface hoar we are hearing about will not help either.

Be careful with wind loaded pockets while approaching and climbing ice routes.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Dry

The new snow will fail naturally off of very steep features and will be susceptible to human triggering in steep areas. Avoid confined features where these events can become focused, and manage your group carefully to avoid getting caught.

The volume of sluffing could knock you over; choose your climb carefully and belay when exposed.Be aware of party members below you that may be exposed to your sluffs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Nov 14th, 2015 4:00PM