Avalanche Forecast

Issued: Mar 4th, 2012 4:00PM

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

snow safety, Avalanche Canada

Little Yoho.

A natural avalanche cycle to size 3 is occurring, and the spike of this system will happen early tomorrow. We may dip into extreme during this time. 48hr. snowfall amounts so far 30cm to 70cm, and rain in Field and Kootenay, 30 cm more possible.SH

Summary

Problems

Persistent Slabs

Snow depths over the Valentines surface hoar and sun crust on steep solar aspects range from 40cm E of the Divide, to 90+cm at Sunshine and Yoho. Continuing warm, dense snowfall and strong winds will increase natural activity on this layer.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Wind Slabs

Fresh and buried wind slabs up to 60cm thick are primed for triggering. They have been seen to step down onto the Valentines surface hoar layer to cause larger avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Deep Persistent Slabs

Recent trips east of the Divide have found a shallow, weak snowpack. Tests done showed sudden collapse results on the basal facets. It is still possible to trigger the entire slope from shallow, thinly covered areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 5th, 2012 4:00PM