Avalanche Forecast

Issued: Mar 2nd, 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 Persistent Slabs.

Avalanche Canada shorton, Avalanche Canada

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Use extra caution around slopes exposed to the sun and high elevation terrain that has been wind affected.

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

TUESDAY NIGHT: Mostly cloudy, moderate southwest wind, treeline temperatures drop to -6 C.

WEDNESDAY: Mix of sun and cloud, moderate southwest wind, freezing level climbs to 1500 m with treeline temperatures around -3 C.

THURSDAY: Mostly sunny, moderate south wind, freezing level climbs to 1900 m with treeline temperatures around 0 C.

FRIDAY: Mostly cloudy with some isolated flurries, moderate south wind, freezing level climbs to 1700 m with treeline temperatures around -2 C.

Avalanche Summary

Since the storm and associated avalanche cycle eased off early last week, there have been daily reports of natural and explosives-triggered avalanches between size 1-3, and human-triggered avalanches between size 1-2. The size and frequency of these avalanches have decreased slightly each day since the storm ended.

The following are reports of a few notable avalanches from the past week:

  • On Friday there was a report of a human-triggered size 2 avalanche that resulted in a full burial in a cutblock near Blue River. Check out the MIN report here.
  • Last Wednesday there were two explosives-triggered size 3 persistent slab avalanches reported on east to southeast aspects around treeline, east of Revelstoke near Albert Canyon. These were notable as they failed on the late January persistent weak layer.

Snowpack Summary

There is around 60-100 cm of now sitting on a persistent weak layer of facets that was buried in mid-February. Deep wind deposits and wind slabs exist in the alpine and open treeline areas.

There is 80-120 cm of snow above the late January persistent weak layer which is composed of surface hoar in sheltered areas in the trees and/ or a crust on steep solar aspects. Very isolated activity on this layer has been observed in the past few weeks.

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.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent (and ongoing) southwest winds are likely forming wind slabs at upper elevations. Previous variable winds may mean that wind slabs could be found on all aspects. The most reactive ones are likely to be found on northerly aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

60-100 cm of snow sits on a persistent weak layer of facets that was buried in mid-February. The late January persistent weak layer is down 70-120 cm. Though avalanches on these layers has been sporadic, they have been large.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Mar 3rd, 2021 4:00PM