Avalanche Forecast

Issued: Jan 16th, 2017 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Deep Persistent Slabs and Loose Dry.

tim haggarty, Parks Canada

Banff Yoho Kootenay.

Incoming snow amounts are uncertain and are likely to vary across the forecast region. What is certain is that this new snow will land on a weak and suspect snowpack.

Summary

Weather Forecast

A large low pressure system is sitting off of the coast and is spinning precipitation towards the forecast region. As much as 35cmÂ is predicted by Thursday in some models favoring the northern part of the region. Other models show very little. In either case expect temperatures to remain mild and winds to remain moderate to strong out of the SW.

Snowpack Summary

Wind slabs at treeline and above have formed over the past week first from North and followed by West winds. These hard slabs can be found in many start zone and open areas overlying a weak, faceted snowpack. In sheltered areas, and at lower elevations, surface snow remains weak and faceted providing poor support for travelers.

Avalanche Summary

A skier accidental sz 1 was reported near treeline on Helen Shoulder Sunday. A skier accidental size 1.5 by Panorama Meadows (Taylor Lake area) was reported Saturday. Both of these events sound as though they released on the deep persistent layer involving slabs over the facets. Numerus loose dry avalanches were observed Sunday at lower elevations.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Problems

Deep Persistent Slabs

The lower half of the snowpack is weak, consisting of facets, decomposing crusts, and depth hoar. Any slab sitting above this should be considered suspect. While these slabs may be difficult to trigger, the result could be a large avalanche.

Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 3

Loose Dry

Weak surface snow found at sheltered locations at lower elevations can fail easily in steep terrain. This loose snow has the potential to entrain more faceted snow and gain mass quickly particularly in confined terrain features like ice climbs

Carry avalanche safety equipment on ice climbs in avalanche terrain.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 17th, 2017 4:00PM