Avalanche Forecast

Issued: Apr 7th, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Fresh snow amounts are variable across the region, and may have formed reactive wind slabs on many aspects due to changing wind directions. 

Keep in mind that even brief periods of sun could initiate avalanche activity in the new snow.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday night - Snow, 5-10 cm / moderate west wind / alpine low temperature near -9 / freezing level at or near valley bottom

Thursday - A mix of sun and cloud / light to moderate northwest wind / alpine high temperature near -8 / freezing level 1100 m

Friday - Snow, 10-15 cm / strong southwest wind / alpine high temperature near -7 / freezing level 900 m 

Saturday - Mainly sunny / light to moderate northwest wind / alpine high temperature near -7 / freezing level 1200 m

Avalanche Summary

Reactive wind slabs may be found on a variety of aspects due to changing wind directions.

A natural avalanche cycle was observed in the region on Saturday during the storm. On Sunday, there were a few size 1-1.5 human triggered wind slab avalanches reported. This MIN describes triggering a small wind slab in large terrain. There were a few small dry loose avalanches reported on Tuesday.

Snowpack Summary

5-10 cm of snow accumulated throughout the day on Wednesday, and another 5-10 is expected to fall on Wednesday night. This adds to the 20 cm that fell over the weekend. The recent precipitation likely fell as rain below around 1000 m. Moderate to strong winds have likely formed wind slabs in lee terrain features.

The new snow sits on a crust on sun-exposed aspects, and on all aspects below 1600 m, and on soft snow or wind slabs on north aspects. 

Cornices are large and looming along ridgelines. Their release is unpredictable, requiring a large berth if you're travelling above or below them.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be aware of highly variable recent wind loading patterns.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

10-20 cm of fresh snow with moderate to strong winds have likely formed reactive wind slabs in lee terrain. Wind slabs may be found on many aspects due to recent variable wind direction.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Cornices

An icon showing Cornices

Cornices are large and looming along many ridgelines, and have likely grown with recent fresh snow and wind.

Aspects: North, North East, East, West, North West.

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 8th, 2021 4:00PM