Avalanche Forecast

Issued: Mar 24th, 2018 3:54PM

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

Avalanche Canada swerner, Avalanche Canada

Strong winds are redistributing the new storm snow, building thicker, reactive slabs. Stick to simple terrain and watch for whumphing and cracking below your feet.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Sunday: Mix of sun and cloud with snow amounts 2-5 cm. Ridgetop wind strong from the West. Alpine temperatures near -7 and freezing levels 900 m. Monday: Mostly cloudy and snow 2-5 cm. Ridgetop wind strong from the southwest. Alpine temperatures near -2 and freezing levels 1200 m. Tuesday: A mix of sun and cloud Ridgetop winds strong-extreme from the West. Freezing levels 1000 m.

Avalanche Summary

On Saturday, ski cutting on convex rolls below treeline produces size 1.5 slabs in the recent storm snow down 30 cm deep. Given the weather forecast storm slabs and wind slabs will continue to be reactive throughout the weekend.

Snowpack Summary

Up to 40 cm of new storm snow overlies a plethora of old snow surfaces including the March 9th and 19th surface hoar existing on high northerly aspects and a melt-freeze crust basically on all aspects at treeline and below. The new storm snow will initially have a poor bond to these buried interfaces. Strong easterly winds have redistributed the new snow onto leeward aspects forming thicker and likely more reactive slabs. Forecast weekend winds from the southwest will likely build new wind slabs on easterly aspects. Deeper in the mid-pack, layers of crusts, facets, and isolated surface hoar buried 50 to 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, sugary facets exist in colder and dryer parts of the region, such as the far north.

Problems

Storm Slabs

An icon showing Storm Slabs
The new snow will likely have a poor bond to the plethora of old snow surfaces, especially where it sits on a melt-freeze crust or surface hoar on high northerly aspects. Changing winds from East to West will build wind slabs on most aspects.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.Stick to simple terrain and be aware of what is above you at all times.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2.5

Valid until: Mar 25th, 2018 2:00PM

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