Avalanche Forecast

Issued: Apr 16th, 2023 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 shorton, Avalanche Canada

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Recent snowfall and wind has left dangerous avalanche conditions in alpine terrain. Carefully investigate the bond of storm snow and give it time to strengthen before committing to avalanche terrain.

Summary

Confidence

Moderate

Avalanche Summary

Reports from the early stages of the storm include a few small (size 1) storm slabs triggered by skiers (an example in this MIN report from Sky Pilot). We suspect some natural avalanches occurred later during the peak of the storm on Sunday, most likely on wind-loaded slopes.

Snowpack Summary

Sunday's cold front will have left 20 to 30 cm of new snow across the region. Storm snow overlies a crust at treeline and below. In the alpine, the snow is heavily wind-affected and 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. Several crusts can be found in the upper snowpack. The lower snowpack is strong and bonded.

Weather Summary

Sunday night

Cloudy with scattered flurries bringing 5 to 15 cm of snow, 30 to 40 km/h southwest wind, treeline temperatures drop to -10 °C.

Monday

Cloudy with flurries starting mid-afternoon with up to 5 cm of snow by the evening, 40 km/h southeast wind, treeline temperatures warm to -5 °C.

Tuesday

Mostly cloudy with scattered flurries bringing 5 to 10 cm of snow, 20 km/h southwest wind, treeline temperatures around -5 °C.

Wednesday

Scattered flurries bring another 5 to 10 cm of snow, 30 km/h southeast wind, treeline temperature climbing to -2 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Carefully monitor the bond between the new snow and old surface.
  • Be especially cautious as you transition into wind affected terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Storm Slabs

An icon showing Storm Slabs

Expect to find storm slabs on steep and wind-loaded slopes. They should bond relatively quickly once the storm eases, but human-triggering will remain a concern.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

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