Avalanche Forecast

Issued: Feb 27th, 2012 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Persistent Slabs, Wind Slabs and Deep Persistent Slabs.

snow safety, Avalanche Canada

Little Yoho.

Lots of settlements on the Valentines surface hoar today, and some areas are just reaching threshold amounts over this layer to become active. Most slopes are waiting for someone to trigger them, and this will be the case for quite some time. SH

Summary

Problems

Persistent Slabs

Snow averages over the Valentines surface hoar and suncrust on steep solar aspects range from 20cm, to over 60cm at Sunshine and Yoho. Lake Louise ski hill reported a natural cycle last night out of bounds to sz. 2., caused by a wind event.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

Moderate winds in the past few days have also created thin, but stiffer wind slab conditions 25-35 cm deep on ridgetop lee terrain. These have been seen to step down to the surface hoar layer.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

On Observation Peak today, we encountered moderate, sudden collapse shears on basal depth hoar. Steep, thin areas mainly E. of the divide will be prone. Lake Louise reported recent, isolated slides triggered on surface hoar which stepped to ground.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 28th, 2012 4:00PM