Avalanche Forecast

Issued: Apr 26th, 2023 4:00PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is below threshold. Known problems include Wind Slabs, Deep Persistent Slabs and Cornices.

Avalanche Canada mconlan, Avalanche Canada

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Travel cautiously and expect to find wind slabs in steep terrain. The possibility remains of triggering buried weak layers.

Summary

Confidence

Moderate

Avalanche Summary

We haven't received any recent avalanche observations.

Going forward, we expect that riders could trigger wind slabs in steep terrain features. The likelihood of triggering a buried weak layer will increase when the freezing level rises on the weekend.

Avoiding cornice exposure is also a good idea, as they are very large and could fail naturally or under the weight of a human.

Snowpack Summary

Wind slabs may be found in steep, lee terrain features from new snow and strong southerly wind. They may sit on a hard melt-freeze crust found up to 1400 m and to mountain tops on sun-exposed slopes. The snow surface could moisten on sun-exposed slopes during any period of sunny skies.

A weak layer of facets and potentially a melt-freeze crust from early January is buried over 100 cm deep in most areas.

Weak faceted grains may exist near the base of the snowpack, particularly in shallower snowpack areas.

Cornices are very large and loom over slopes below.

Weather Summary

Relatively cool and snowy conditions are expected leading into the weekend, with 10 to 20 cm of snow possible along with strong southerly wind. Warm air is then incoming for Saturday, bringing the freezing level to around 2300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • Cornice failure may trigger large 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

Snow and strong wind have likely formed new wind slabs in lee terrain features at higher elevations. Assess for slabs in steep terrain before committing yourself.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Weak layers may be found in the middle and near the base of the snowpack, which are likely to reawaken with the variety of weather we receive during the spring. Small avalanches and cornice falls have the potential to trigger these deeper layers.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

2 - 3.5

Cornices

An icon showing Cornices

Cornices are large at this time of year and will become more prone to fail as they warm up with spring weather. Stay well back from them when on ridgelines and limit your exposure when travelling on slopes below them, as their release is unpredictable. Cornice falls could trigger very large slab avalanches on slopes below them.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Apr 27th, 2023 4:00PM

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