Avalanche Forecast

Issued: Mar 30th, 2018 4:30PM

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

Avalanche Canada mconlan, Avalanche Canada

New and old storm slabs aren't bonding well to underlying layers. Be cautious on southerly aspects when the sun is out. Conservative decision-making is recommended.

Summary

Confidence

Moderate -

Weather Forecast

SATURDAY: Mostly sunny, light southwesterly winds, alpine temperature -10 C, freezing level 600 m.SUNDAY: Cloudy with early morning snowfall then partly cloudy, accumulation 2 to 5 cm, light northeasterly winds, alpine temperature -10 C, freezing level 600 m.MONDAY: Partly cloudy with afternoon snowfall, light southerly winds, alpine temperature -9, freezing level 500 m.

Avalanche Summary

On Thursday, small (size 1.5) storm and wind slabs were remotely triggered by skiers at all elevation bands, 30 to 40 cm deep, on north to westerly aspects. A large (size 2.5) deep persistent slab was also remotely triggered in a shallow, rocky, alpine snowpack area, with a depth of about 50 cm.Evidence of a widespread avalanche cycle was observed on Wednesday. Large to very large (size 3 to 3.5) storm slabs were observed, often in southeast, east, and northeast slopes. Some of these stepped down to weak and sugary facets at the bottom of the snowpack.

Snowpack Summary

Thursdays storm brought up to 35 cm of snow to the southern parts of the region, such as around Smithers. This overlies last weekends storm snow, which has settled into a reactive slab and is not bonding well to old snow surfaces that are about 50 cm deep. These include two layers of surface hoar, which exist on shaded aspects at high elevations as well as a melt-freeze crust on all aspects at treeline and below treeline elevations.Deeper in the snowpack, layers of crusts, facets, and isolated surface hoar buried about 100 cm exist from mid- and late-February and a surface hoar/crust layer from January is buried around 150 to 200 cm. Near the bottom of the snowpack, weak and sugary facets exist, particularly in steep, rocky, and shallow snowpack areas. Shallower storm slabs have stepped down to these facets recently, producing very large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm slabs exist in the south of the region and older slabs exist in the north.  Very large avalanches have occurred, as the slabs are not bonding well to underlying layers of surface hoar, crusts, or sugary facets in thin snowpack areas.
Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Observe for signs of instability, such as cracking, whumpfing, and avalanche activity.Approach lee and cross-loaded slopes with caution.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3.5

Valid until: Mar 31st, 2018 2:00PM

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