Avalanche Forecast

Issued: Mar 28th, 2018 4:16PM

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

Avalanche Canada mbender, Avalanche Canada

In the north of the region, recent new snow may be sitting on a weak layer of facets or surface hoar on shady aspects in the alpine and tree line.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

THURSDAY: Mostly cloudy with isolated flurries in the north. Flurries in the south, accumulation 5cm / Moderate to strong west wind / Alpine temperature -3 / Freezing level 1300 m FRIDAY:  Mostly cloudy with isolated flurries in the north. Flurries in the south, accumulation 5-10cm / Light to moderate southwest wind / Alpine temperature -2 / Freezing level 1400 m SATURDAY: Mix of sun and cloud / Light to moderate southeast wind / Alpine temperature -1 / Freezing level 1600 m

Avalanche Summary

Reports on Monday from the north of the region show several skier triggered and natural storm slab avalanches size 1.5 to 2.5 running on either facets or surface hoar on north through east aspects in the alpine and tree line. On Sunday there was a report of a skier triggered storm slab (size 1) on a westerly aspect in the high alpine, as well as sloughing in steep terrain.

Snowpack Summary

Last weekend's storm snow totals are 20-40 cm of recent storm snow that sits on a crust that is present at all elevations on solar aspects as well as low elevation northerly aspects. On northerly and east aspects at treeline and alpine elevations the storm snow sits on a mix of large surface hoar and or facets.Deeper in the snowpack in the north of the region, north and east aspects are harboring cold snow and a surface hoar layer buried early March that is about 40-60 cm below the surface. This layer exists at alpine and treeline elevations, but it is not everywhere. This layer has produced large human triggered avalanches in the north of the region in the past week. Also in the north of the region a weak layer buried mid-February is about 60 to 80 cm below the surface and has been reactive in snowpack tests. The layer is composed of sugary facets, a sun crust on solar aspects, and surface hoar that is present at and below treeline. In the south of the region, around the Coquihalla and in Manning Park, the recent storm snow overlies a recent crust that caps a well settled snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow and strong winds have built storm and wind slabs. These slabs will add to recent storm snow that overlies an old surface of crusts and surface hoar and has been reactive at treeline and above in the north of the region.
Use ridges or ribs to avoid pockets of wind loaded snow.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable snowpack.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 29th, 2018 2:00PM

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