Avalanche Forecast

Issued: Mar 28th, 2021 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Strong winds shifting northwest overnight will continue to redistribute recent storm snow into deep slabs. Give the new snow time to settle and stabilize before pushing into bigger terrain. Crusty surfaces below treeline will make for low hazard but difficult travel conditions.

Summary

Confidence

Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.

Weather Forecast

Sunday night: Flurries bringing up to 5 cm. Moderate northwest wind. Freezing level dropping to valley bottom. Alpine temperature -15.

Monday: Mix of sun and cloud. Light to moderate northwest wind. Freezing level valley bottom. Alpine temperature -15.

Tuesday: Mostly cloudy. Light to moderate westerly wind. Freezing level 1300 m. Alpine temperature -7.

Wednesday: Sunny. Light to moderate southwest wind. Freezing level 1800 m. Alpine temperature -1.

Avalanche Summary

We are still awaiting reports of avalanche activity from the weekend's storm. A widespread natural cycle is likely to have occurred Sunday. 

On Saturday, evidence of an old size 2 cornice failure was observed at Allen Creek. Otherwise, we have no reports of avalanche activity since Wednesday's storm when there were a few reports of natural and human triggered storm slab avalanches.

Snowpack Summary

The weekend's storm dropped another 20-50 cm of new snow over the region. This snow has likely been redistributed by strong wind, switching from southwest to northwest Sunday night. Crusty surfaces exist below treeline.

The new snow buries old stubborn slabs at upper elevations and a crust below treeline. Recent warm weather patterns are expected to have helped old persistent weak layers heal. The new snow load (and whether it triggers deeper slabs during the storm) may help shed some light on concerns over a facet layer 150 cm deep from the mid-February cold snap that resulted in few large cornice triggered avalanches in the first half of March.

Terrain and Travel

  • Be careful to keep storm day fever from luring you out into bigger terrain features.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Seek out sheltered terrain where new snow hasn't been wind-affected.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

Problems

Storm Slabs

An icon showing Storm Slabs

Storm slabs are most likely to remain reactive in wind loaded terrain features. Wind direction has varied from southwest to northwest so watch for these deep pockets on a variety of aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices are likely fragile due to rapid growth with recent snow and wind.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Mar 29th, 2021 4:00PM

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