Avalanche Forecast

Issued: Apr 12th, 2024 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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Assess for wind slabs at higher elevations. Small avalanches could step down to a deeper layer and form large avalanches.

Summary

Confidence

Moderate

Avalanche Summary

Many slab avalanches were observed in the north of the region on Thursday. The avalanches were triggered naturally and by riders in alpine terrain on all aspects. The avalanches were 40 to 80 cm deep and occurred within the recent storm snow as well as on the weak layer described in the Snowpack Summary.

Looking forward, riders could trigger similar avalanches this weekend. Small avalanches could step down to the deeper layer, forming large avalanches.

Snowpack Summary

Recent snow and southwest wind formed wind slabs in lee terrain features at higher elevations, which may take a couple days to bond to the snowpack.

Around 50 to 100 cm of snow overlies a hard melt-freeze crust from early April. This snow is slow to bond to the crust where pockets of weak surface hoar or faceted grains rest on the crust, which is most likely on northerly aspects at treeline and alpine elevations.

There are no deeper concerns at this time.

Weather Summary

Friday Night

Cloudy with 1 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.

Saturday

Cloudy with 1 to 3 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1000 m.

Sunday

Cloudy with 5 cm of snow. 20 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1000 m.

Monday

Cloudy with 5 to 10 cm of snow. 20 km/h west ridgetop wind. Treeline temperature -4 °C. Freezing level 900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Carefully evaluate steep lines for wind slabs.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Wind Slabs

An icon showing Wind Slabs

Assess for wind slabs in steep lee terrain features. Small wind slabs could step down to a weak layer over a hard crust buried around 50 to 100 cm deep, forming large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Apr 13th, 2024 4:00PM

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