Avalanche Forecast

Issued: Mar 19th, 2017 4:00PM

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

Avalanche Canada mbender, Avalanche Canada

Continually reassess conditions as you travel into avalanche terrain and be aware of the potential for deeper weaknesses in the snowpack

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

MONDAY: Mainly cloudy / Light to moderate east wind / Alpine temperature 2 / Freezing level 1400mTUESDAY: Periods of wet snow or rain, accumulation 5-10cm / Light to moderate southeast wind / Alpine temperature 3 / Freezing level 1700mWEDNESDAY: Periods of wet snow or rain, accumulation 5cm / Light to moderate southwest wind / Alpine temperature 3 / Freezing level 1700m

Avalanche Summary

On Saturday in the north part of the region, a size 3 natural avalanche was reported to have triggered in the storm snow and stepping down to one of the February weak layers. Explosive control produced a few size 2-2.5 storm slabs and a few natural storm slabs were reported in the northern part of the region. On Friday, a large cornice fall missed a group of skiers on a north aspect in the Duffey area. Click here to See a MIN report for details. On Monday, storm and wind slabs may remain reactive in human triggers at upper elevation. In northern parts of the region, the deeper February weak layers continue to present a low probability / high consequence scenario.

Snowpack Summary

Storm snow amounts from Saturday totalled roughly 40 cm around Coquihalla and Allison Pass and 30 cm around Duffey Lakes. Freezing levels reached roughly 1400 m, resulting in rain and/or wet snow at lower elevations. Thicker wind slabs and large cornices likely exist in alpine terrain. The storm snow sits above a widespread rain crust up to about 2100 m, but the snow will likely form a good bond to this crust. In the north of the region, the February weak layers are 80-120 cm deep and include a buried surface hoar layer that recently produced a few persistent slab avalanches and a crust/facet layer that appears to be gaining strength. In the southern parts of the region, the lower snowpack is generally stable.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs may remain reactive at higher elevations and wind-affected terrain.
Avoid freshly wind loaded features.Be alert to conditions that change with elevation.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
Heavy triggers such as a cornice fall or a small avalanche could potentially step down to weak layers buried about 1 m deep in the northern parts of the region.
If triggered, storm slabs may step down to deeper layers resulting in very large avalanches.Pay attention to overhead hazards like cornices which could trigger persistent slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Mar 20th, 2017 2:00PM

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