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Avalanche Forecast

Mar 31st, 2018–Apr 1st, 2018
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Purcells.

Slab avalanches continue to be reactive to human triggers at higher elevations. Danger will increase as a storm hits the region on Sunday night.

Confidence

Moderate - Forecast snowfall amounts are uncertain

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: Cloudy then flurries bring 2-5 cm of snow by the afternoon then intensifying in the evening with another 10-20 cm possibly overnight, moderate southwest wind, freezing level up to 1200 m, and alpine high temperatures near -6 C.MONDAY: Flurries continue into the morning then ease off in the afternoon, light wind, freezing level up to 900 m, and alpine high temperatures near -8 C.TUESDAY: Mix of sun and cloud, light wind, freezing level up to 1300 m, and alpine high temperatures near -5 C.

Avalanche Summary

On Saturday a skier triggered a large slab avalanche (size 2.5) on a south aspect at 2600 m. The avalanche failed on a buried sun crust 150-200 cm below the surface.Several size 1-2 natural wind slabs and storm slabs were reported on a range of aspects on Thursday and Friday. A few size 1 skier triggered slabs on were reported on south aspects around 2300 m, including one that partially buried a skier.On Wednesday, several skier triggered avalanches up to size 2.5 were reported from all aspects above 2000 m. These avalanches predominantly failed on the late-March interface, with crown depths from 20-50 cm deep and up to 100 cm in some areas.

Snowpack Summary

Snowfall amounts have been variable over the past week, with areas just east of Kootenay Lake receiving up to 80 cm of snow and eastern parts of the region receiving only 20-40 cm. 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. Other slightly deeper surface hoar/facet layers have been reported on shaded aspects at higher elevations and may be found approximately 40-60 cm below the surface.Deeper persistent weak layers from mid-late February as well as January and December layers, are still being monitored by professional observers, but are generally considered dormant. Facets also linger at the base of the snowpack.

Avalanche Problems

Wind Slabs

Human-triggered slab avalanches remain a concern. Wind-affected features on all aspects are suspect, as are steep south aspects where storm slabs may sit above buried sun crusts.
Use conservative route selection, choose moderate angled and supported terrain with low consequence.Minimize exposure to steep south-facing alpine slopesAvoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2.5