Avalanche Forecast

Issued: Mar 29th, 2021 4:00PM

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

Avalanche Canada ahanna, Avalanche Canada

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Storm slabs may remain reactive to human triggers as natural avalanche activity tapers off. Start with small terrain features, look for signs of instability and gather information before considering bigger terrain.

Summary

Confidence

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

Weather Forecast

Monday night: Partly cloudy. Light to moderate northwest wind. Freezing level valley bottom. Alpine temperature -13.

Tuesday: Mix of sun and cloud. Light northwest wind. Freezing level 1500 m. Alpine temperature -9.

Wednesday: Sunny. Light southwest wind. Freezing level 2100 m. Alpine temperature -1.

Thursday: Sunny. Light southwest wind. Freezing level 2100 m. Alpine temperature -1.

Avalanche Summary

Preliminary reports of avalanche activity during the storm on Sunday include a numerous explosive triggered size 2 loose wet avalanche on a northeast aspect around 1700 m. It is suspected to have scrubbed down to a crust near the ground, as rain and warm temperatures destabilized the full depth of the snowpack.

Snowpack Summary

15-40 cm of recent snow came with west to northwest wind, likely loading the fresh snow into lee features at upper elevations. Crusty and/or moist surfaces exist below treeline depending on elevation and time of day.

A widespread crust layer from the mid-March warm spell can be found 30-60 cm deep, and small surface hoar has been observed at this depth on some isolated north-facing slopes. Reports suggest the snow is generally well bonded to these layers. Deeper layers are strong and have been unreactive over the past few weeks. 

Terrain and Travel

  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Start with conservative lines and watch for clues of instability.
  • 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 may remain reactive to human triggers in wind loaded terrain features. 

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.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 2.5

Valid until: Mar 30th, 2021 4:00PM