Avalanche Forecast

Issued: Mar 5th, 2021 4:00PM

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

Avalanche Canada astclair, Avalanche Canada

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The snowpack is adjusting to a massive new load of snow. Continue to make conservative terrain choices while the storm snow settles and stabilizes. Avoid exposure to cornices and wind-drifted areas.

Summary

Confidence

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

Weather Forecast

A parade of storms continues through the weekend

Friday night: Overcast, 5-10 cm of snow, moderate southwest winds, freezing level dropping to 800 m. 

Saturday: Mostly cloudy, scattered flurries with up to 5 cm of snow, light southwest wind, freezing level near 1100 m. 

Sunday: Mostly cloudy, 15-25 cm of snow, moderate south wind, freezing level near 1000 m. 

Monday: Partly cloudy, isolated flurries with trace accumulations, light east wind, freezing level near 1200 m.

Avalanche Summary

On Friday, operators reported several small (size 1) storm slab avalanches from ski cuts at treeline and belowtreeline elevations, as well as small natural loose wet avalanches below 1600 m.

Snowpack Summary

Impressive snow totals of 50-80 cm blanketed slopes above 1600 m across the region on Friday. This snow was accompanied by strong south winds, forming touchier slabs on leeward slopes. Massive cornices exist on ridgelines, which can act as triggers on slopes below. A cooling trend over the weekend is expected to settle and strengthen lower elevation slopes that became saturated with rain. 

In isolated areas with a shallower snowpack in the region, a layer of facets, spotty surface hoar, and/or crusts buried in mid-February may still be preserved. There have been no avalanches reported on this layer; however, large triggers, such as an avalanche in motion, cornice fall, or intense loading from snow and wind have the potential to this deeper layer in areas where it may still exist.

The mid and lower snowpack is well settled and strong in most areas.

Terrain and Travel

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Cornice failure may trigger large avalanches.
  • Stick to simple terrain and be aware of what is above you at all times.

Problems

Storm Slabs

An icon showing Storm Slabs

50-80 cm of snow rapidly accumulated on Friday, forming a widespread reactive storm slab problem. These slabs will be more reactive in wind-drifted areas and will require time to heal.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1.5 - 3

Cornices

An icon showing Cornices

Cornices are large and looming, and they may release naturally under the current conditions. Cornice falls can act as triggers on slopes below.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Mar 6th, 2021 4:00PM

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