Avalanche Forecast

Issued: Mar 20th, 2018 5:01PM

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

Avalanche Canada cgarritty, Avalanche Canada

Your hunt for sheltered snow is likely to lead you to the same areas where storm slabs are a concern. Stick to supported slopes to limit your exposure.

Summary

Confidence

High -

Weather Forecast

Wednesday: Cloudy with isolated flurries and a trace of new snow. Light to moderate southeast winds, increasing overnight. Freezing level to 1600 metres with alpine high temperatures around -4.Thursday: Cloudy with isolated flurries and a trace of new snow, increasing overnight. Strong southeast winds. Freezing level to 2000 metres with alpine high temperatures around 0.Friday: Mainly cloudy with continuing isolated flurries and a trace of new snow. Moderate to strong southwest winds. Freezing level to 1300 metres with alpine high temperatures around -6.

Avalanche Summary

Reports from Monday included another ski cut storm slab (size 1) on a high north aspect in the southern part of the region.Sunday's reports included two small skier-triggered storm slabs that released on a north aspect in the alpine. Their crown fractures were 25 cm deep.Last Wednesday there were reports of several natural, loose, wet avalanches up to size 1.5 on south aspects at all elevations, as well as a skier triggered wind slab (size 1) on a northeast aspect at 2300 m.

Snowpack Summary

Recent light snowfalls have been followed by warm daytime temperatures and glimpses of sun, setting up a couple of thin storm snow layers over temperature and sun crusts at lower elevations and on south aspects. On shaded aspects at higher elevations, these snowfalls have buried and preserved a couple of surface hoar layers now found up to 25 cm deep. The deepest of these surface hoar layers has been the failure plane in several recent slab avalanches.New snow amounts taper with elevation and below 1800 m, minimal accumulations have buried a supportive crust on all aspects. This crust will likely break down with daytime warming, becoming moist in the afternoon. Persistent weak layers from early January and mid-December are still being reported by local operators. They are generally considered dormant, but could wake up with a surface avalanche stepping down, a large cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets.

Problems

Storm Slabs

An icon showing Storm Slabs
Isolated pockets of surface hoar on sheltered, high north aspects have led to prolonged reactivity of storm slabs about 25 cm deep. Isolated wind slabs and mature cornices are other hazards to manage at higher elevations.
Give cornices a wide berth when travelling on or below ridges.Use extra caution in the afternoon if the snow becomes moist or wet.Be cautious around steep or convex slopes where buried surface hoar may be preserved.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 21st, 2018 2:00PM

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