Avalanche Forecast

Issued: Nov 26th, 2014 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 Deep Persistent Slabs.

snow safety, Parks Canada

Banff Yoho Kootenay.

The first big storm of the winter is beginning now, along with the first avalanche cycle of the winter for Thursday and Friday. Ice climbers should stay away from avalanche gullies, and skiers be aware that the snowpack is weak and unstable. GS

Summary

Weather Forecast

A significant storm embedded in a westerly flow will cross the regions with periods of snow starting Wednesday evening, depositing 50-60 cm by Friday morning. Treeline temperatures will range from -5 to -10 with moderate SW winds, gusting to strong. Following this storm, skies will clear and temperatures will plummet to -30 on Saturday.

Snowpack Summary

A weak and almost entirely facetted snowpack exists across the forecast region at this time. With the arrival of the current storm starting on Wednesday night, upwards of 50-60 cm additional snow could fall by Friday. This will most certainly overload the weak base, and slab avalanches are expected at treeline and above.

Avalanche Summary

No new avalanche observed or reported today.

Confidence

Problems

Storm Slabs

Weak layers formed during this storm will create avalanche issues at and near the storm snow interface. Watch for slabs in all leeward areas in addition to loose snow avalanches in gullies. Ice climbers should limit their exposure.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

The new snow will overload a very weak base and cause avalanches running on the ground. Getting caught in an avalanche like this will result in an awful ride through trees and rocks. Avoid all open avalanche terrain during this storm.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Nov 27th, 2014 4:00PM