Avalanche Forecast

Issued: Nov 12th, 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.

With large amounts of snow currently showing in forecasts, we expect avalanche activity to begin Friday and continue through the weekend. TH

Summary

Weather Forecast

A powerful low will exert its influence over the region beginning Thursday evening. Accumulations of 50-100 cm of snow at treeline, high winds, and freezing levels rising to near 2000 m have been forecast to appear by the time the system passes on Sunday. With the heavy loading expected, an avalanche cycle will likely begin on Friday.

Snowpack Summary

35-45 cm of unconsolidated snow exist at treeline elevations throughout the forecast area. A 5mm layer of surface hoar that was reported in some areas has been buried by several cm of new snow yesterday (November 11 surface hoar). Some soft wind slabs exist at higher alpine elevations.

Avalanche Summary

Over the past five days slabs and loose snow avalanches (up to size 2.5) have been triggered and are running naturally from alpine features. Tuesday, at Bow Summit, a size 1.5 avalanche was remotely triggered on the ground, and on the Wapta a group remotely triggered a size 2 on Mt. Olive.

Confidence

Intensity of incoming weather systems is uncertain on Thursday

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 2

Valid until: Nov 13th, 2015 4:00PM