Avalanche Forecast

Issued: Mar 29th, 2018 4:20PM

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

mbender, Avalanche Canada

Kootenay Boundary.

Recent new snow and moderate to strong northwest winds have created wind slabs at upper elevations. These may be most reactive on shady aspects. Reduce your exposure to sunny slopes if the sun makes an appearance.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

FRIDAY: Mix of sun, cloud and isolated flurries / Moderate northwest wind / Alpine temperature -2 / Freezing level 1600m SATURDAY: Mix of sun and cloud / Light southeast wind / Alpine temperature -5 / Freezing level 1300m SUNDAY:Â Mix of sun, cloud and isolated flurries / Moderate southwest wind / Alpine temperature -4 / Freezing level 1500m

Avalanche Summary

Tuesday's reports focus on a few natural storm slab avalanches size 1.5-2 on northeast and northwest aspects at 2200m. On Monday there were reports of numerous explosives and naturally triggered storm slab avalanches size 1.5-2 on all 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 releases 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

30-60 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 tree line 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.

Problems

Wind Slabs

Southwest wind combined with recent snowfall have formed fresh storm and wind slabs that that may be most reactive on shady aspects where they may be sitting on weak surface hoar or facets.

Use ridges or ribs to avoid pockets of wind loaded snow.Extra caution needed around cornices with current conditions.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 30th, 2018 2:00PM