Avalanche Forecast

Issued: Mar 17th, 2023 4:00PM

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

Avalanche Canada JH, Avalanche Canada

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Great skiing can still be found on shaded slopes.

Expect a surface crust on solar aspects in the morning, and scale back your exposure as this switches from crusty to moist/wet in the afternoon.

Summary

Confidence

Moderate

Avalanche Summary

On Friday, we observed a few loose snow avalanches on steep solar aspects in the Highway corridor, up to size 2.5.

There was a widespread cycle of avalanche activity on steep solar aspects on Thursday. These were primarily loose snow avalanches in the size 1-2 range, with a few larger (size 3) avalanches in the steep paths off of Mt. Tupper. There was also skier triggered size 1.5 slab avalanche reported in 8812 bowl. All activity was suspected to be failing on the March 11th crust.

Field teams were able to ski cut size 1-1.5 slabs on small steep unsupported solar features (buried crust) on Tuesday and Wednesday.

Snowpack Summary

Up to 40cm of recent snow is settling over a variety of old surfaces (sun crust, surface hoar and soft facetted snow). This storm snow will take longer to bond where it sits on a crust/surface hoar combo.

Below this is a generally strong snowpack, however the basal weakness of rounding facets/decomposing crust persists near the ground and should factor in to your terrain use decisions.

Weather Summary

High pressure will maintain stable weather through the weekend.

Tonight: Clear periods. Alpine low -6°C. Light Southwest ridgetop winds.

Saturday: Mix of sun and cloud. Alpine High -5°C, freezing level (FZL) 1500m. Light S ridgetop winds.

Sunday: Sunny periods. Low -7°C, High -2°C, FZL 1800m. Light SE winds.

Monday: Mainly cloudy. Low -5°C, High -1°C, FZL 1800m. Light wind.

Terrain and Travel Advice

  • Avoid sun exposed slopes, especially if snow surface is moist or wet.
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.

Problems

Loose Wet

An icon showing Loose Wet

As the sun heats up solar slopes expect the surface snow to loose stability and trigger easily in steep terrain.

Aspects: South East, South, South West, West.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Storm Slabs

An icon showing Storm Slabs

The recent snow from Monday (March 11th) is sitting over a crust/surface hoar combination in some locations. This layer has been reactive in tests and to skier traffic and will become easier to trigger on solar slopes as they warm up.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Mar 18th, 2023 4:00PM