Avalanche Forecast

Issued: Mar 31st, 2018 4:02PM

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

Avalanche Canada simonhorton, Avalanche Canada

Another storm will keep the danger elevated on Sunday and Monday. Fresh snow from the past week is capable of producing large avalanches, so a conservative approach to terrain is recommended.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Sunday

Weather Forecast

A low pressure system passing through the region on Sunday night will bring snow, but the amounts are fairly uncertain and could be highly variable.SUNDAY: Flurries intensifying throughout the day with 5-10 cm of snow by the afternoon and then another 10-20 in the evening, light southwest wind, freezing level up to 1200 m, and alpine high temperatures near -6 C.MONDAY: Snow continues in the morning bringing another 5 cm then easing off in the afternoon, freezing level up to 900 m, and alpine high temperatures near -8 C.TUESDAY: Mostly cloudy, light wind, freezing level up to 1300 m, and alpine high temperatures near -5 C.

Avalanche Summary

Widespread avalanche activity occurred in the top 30 cm of new snow on Friday. Numerous natural and skier triggered size 1 avalanches were reported, with the most reactive conditions on wind-affected slopes at treeline on north and east aspects.On Thursday, several size 1 skier triggered storm slab avalanches were reported. They were 30-50 cm thick and occurred on north and east aspects above treeline. One of the slabs subsequently triggered a larger size 2 avalanches that ran on the late-March crust. Some natural size 2-3 storm slabs avalanches were also reported in alpine terrain and a cornice fall on a north aspect in the Selkirks triggered a size 2.5 avalanche on an unidentified 2 m deep weak layer.

Snowpack Summary

Another 10-25 cm of snow on Friday brings the weekly total to 40-80 cm, with amounts tapering with elevation.The storm snow sits on an interface buried in late-March that consist of crusts below 1900 m and on south aspects, and surface hoar on shaded aspects at higher elevations.Pockets of surface hoar (buried mid-March) have been reported on shaded aspects at higher elevations and may be found approximately 60-80 cm below the surface.Deeper persistent weak layers from January and December are still being reported by professional observers, but are generally considered dormant.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm slabs will remain reactive to human triggering this long weekend. Wind-affected features on north and east aspects are suspect, as are steep south aspects where storm slabs may sit above buried sun crusts.
Be careful with wind loaded slopes, especially near ridge crests and roll-overs.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Minimize exposure to steep south-facing slopes

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Apr 1st, 2018 2:00PM

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