Avalanche Forecast

Issued: Mar 27th, 2018 4:13PM

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

Avalanche Canada mbender, Avalanche Canada

Recent snow and wind have built slabs in recent days. Assess the bond between the new snow and the old snow surface before committing to bigger slopes.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

WEDNESDAY: Mix of sun and cloud / Light northwest wind / Alpine temperature -4 / Freezing level 1500 m. THURSDAY: Mostly cloudy with isolated flurries / Light to moderate west wind / Alpine temperature -3 / Freezing level 1500 m. FRIDAY: Mix of sun, cloud and isolated flurries / Light west wind / Alpine temperature -1 / Freezing level 1600m

Avalanche Summary

On Monday there were reports of numerous explosives triggered storm slab avalanches size 1.5-2 on northwest to northeast aspects in the alpine and tree line. Sunday there was a report of a natural size 2 wind slab and a skier triggered size 1 wind slab release. Both of these were on northeasterly aspects above 2000 m. Also on Sunday explosive control work produced numerous size 1.5-2 storm slab results all failing in the recent storm snow (25-40 cm deep) on north and northwest aspects above 2000 m.Saturday we received reports of several remotely (from a distance) triggered and skier-triggered size 2 storm slab release that failed 40-50 cm deep on a mix of buried crusts, surface hoar and facets. Explosive control work also produced size 1.5-2 storm slab results running on a crust on southeast aspects from 1900 -2000 m. Read more here. And here.

Snowpack Summary

Around 30-40 cm of recent snow sits on a crust at all elevations on solar aspects and all aspects below 1900 m elevation. On northerly aspects at and above treeline the storm snow is burying a mix of large surface hoar and surface facets. Two other weak layers are present in the upper snowpack. A layer buried mid March is down 30 to 60cm is crust on solar aspects and surface hoar on high elevation north. A layer buried early March is 50 to 80cm below the surface and is similar in composition to those just described.A few other persistent weak layers are buried in the mid and lower snowpack, but they have gone dormant and are unlikely to resurface until we move into a period with consecutive above-freezing nights later in the spring.

Problems

Storm Slabs

An icon showing Storm Slabs
Southwest wind combined with recent snowfall have formed fresh storm and wind slabs that sit on a mix of crusts, surface hoar and facets.
Use caution on steep slopes and convex rolls.Whumpfing, shooting cracks and recent avalanches are all strong indicators of unstable storm snow.Use caution in lee areas in the alpine and treeline. Storm snow and wind have formed touchy slabs.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 28th, 2018 2:00PM