Avalanche Forecast

Issued: Apr 16th, 2023 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 shorton, Avalanche Canada

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Heightened avalanche conditions exist on wind-affected slopes where there could be deep deposits of new snow.

Summary

Confidence

Moderate

Avalanche Summary

No new avalanches were reported over the weekend (at the time of publishing), however, some wind slab avalanches may have occurred during the peak of the storm on Sunday.

Last week, several remotely triggered storm and wind slab avalanches were reported. They typically occurred between 2000 and 2300 m and on a variety of aspects. A layer of facets and/or a crust down around 60 cm is likely responsible. Check out this MIN report for an example of these avalanches.

Snowpack Summary

The recent storm only delivered 5 to 15 cm of snow to this region, but strong southerly wind would have formed deeper and potentially reactive wind slabs on lee terrain features. This snow overlies a crust at treeline and below. In the alpine, this snow sits over a variety of layers including dry snow and wind slabs on north aspects and sun crusts and wind-pressed snow on south aspects.

A layer of facets and a crust from early April can be found down up to 60 cm at treeline and above.

The base of the snowpack remains faceted and weak. Avalanche activity has not been observed on this layer recently, but concern remains for shallow rocky snowpack areas.

Weather Summary

Sunday night

Scattered flurries with 5 cm of snow, 30 to 40 km/h southwest wind, treeline temperatures drop to -12 °C.

Monday

Clear periods in the morning, then increasing cloud in the afternoon, no significant precipitation, 20 km/h south wind, treeline temperatures warm to -6 °C.

Tuesday

2 to 4 cm of new snow overnight then mix of sun and cloud during the day, 20 km/h southwest wind, treeline temperatures around -5 °C.

Wednesday

Mix of sun and cloud, isolated flurries with trace amounts of snow, 20 km/h south wind, treeline temperatures around -4 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be carefull around freshly wind loaded features.
  • Use ridges or ribs to avoid areas of wind loaded snow.
  • Remote triggering is a concern, watch out for adjacent and overhead slopes.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Ongoing snowfall and strong south wind may have formed wind slabs on lee terrain features. A layer of facets and a crust down 60 could result in larger slab avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Cornices

An icon showing Cornices

Recent snowfall and southerly wind have grown cornices and made them more likely to fail.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 17th, 2023 4:00PM

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