Avalanche Forecast

Issued: Apr 19th, 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.

Avalanche Canada mconlan, Avalanche Canada

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Wind slabs may linger in lee terrain features. Small avalanches could step down to a buried layer and form large avalanches.

Summary

Confidence

Moderate

Avalanche Summary

We haven't received any recent reports of avalanche observations. The most recent avalanches occurred about a week ago on the facet layer described in the Snowpack Summary (e.g., this MIN).

Snowpack Summary

Around 10 to 20 cm of snow fell since the weekend with periods of strong southerly wind, which may have formed wind slabs in lee terrain features. The snow may not bond well to underlying layers, including faceted snow in shaded aspects at high elevations or a hard melt-freeze crust found on all aspects up to 1700 m and to mountain tops on southerly slopes.

A layer of facets and a crust from early April is buried up to 60 cm at treeline and alpine elevations. There's uncertainty in how this layer is bonding, but it was the culprit of many large avalanches around April 12.

The base of the snowpack remains faceted and weak. We haven't received any notes of recent avalanche activity on this layer, but the concern remains for steep and rocky slopes with a thin snowpack.

Cornices are large and looming at this time of year.

Weather Summary

Wednesday Night

Clear skies with no precipitation, 10 km/h southwest wind, treeline temperature -7 °C.

Thursday

Cloudy with afternoon snowfall, accumulation 1 to 3 cm, 20 to 40 km/h south wind, treeline temperature -6 °C, freezing level 1200 m.

Friday

Cloudy with snowfall, accumulation 5 cm, 20 km/h southwest wind, treeline temperature -3 °C, freezing level 1600 m.

Saturday

Cloudy with snowfall, accumulation 2 to 5 cm, 20 to 40 km/h south wind, treeline temperature -1 °C, freezing level 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Approach lee and cross-loaded slopes with caution.
  • 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

Wind slabs may linger in lee terrain features from recent snow and strong southerly wind. Small avalanches could step down to a layer of facets and a crust buried 60 cm that could result in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 20th, 2023 4:00PM

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