Bulletin d’avalanche

Lizard-Flathead

Apr 21 – 22, 2023Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible

Points saillants

Expect to find fresh and reactive wind slabs forming over the day. Avoid areas with visibly wind-affected snow, or where active wind transport is occurring.

Sheltered features likely still hold dry, loose snow with great riding conditions. Limit your exposure to sun-affected slopes if the sun comes out in your area.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2

    As winds increase over Saturday expected new wind slabs to form on north and east facing slopes at treeline and above. Watch for wind loading as you transition to and from ridgeline features.

    Snowfall amounts were higher as you head further east - giving potential for larger slabs.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Loose dry snow sits in sheltered terrain features. Manage your sluff in steep and consequential terrain.

    Be alert to changing conditions when daytime heating and direct sun are impacting slopes. Rocks will heat up with daytime warming and may become trigger points for loose avalanches.

Confidence

Moderate

Avalanche Summary

On Thursday numerous small natural avalanches were observed as the sunshine affected the new snow. Rider triggered avalanches were also reported, failing under the new snow, on the buried crust.

On Wednesday a large (size 2.5) skier trigger avalanche was reported west of Fernie. This avalanche started at 1700 m on a south facing slope and ran for approximately 700 m. See this MIN report for further information and photos.

If you head out in the backcountry, let us know what you are seeing by submitting a report to the Mountain Information Network.

Snowpack Summary

In the alpine and around treeline elevations, 10-30 cm of recent snow covers a crust. Below treeline, expect to find moist or refrozen surfaces, and a shrinking snowpack that is isothermal during the heat of the day.

The mid snowpack is generally settled and strong, except in areas with snow depths less than 150 cm. In these lower snow areas, the mid-pack is likely weaker and more faceted.

The lower snowpack includes a layer of weak sugary crystals near the ground. This layer has shown signs of gaining strength, and it has not produced recent avalanche activity in this area.

Weather Summary

Friday Night

Mainly clear with isolated flurries, and trace accumulations of snow. Light to moderate west wind. Freezing levels drop to 500 m overnight.

Saturday

Mostly cloudy with isolated flurries, and trace accumulations of snow. Light to moderate westerly wind. Freezing levels rise from valley bottom to 2000 m.

Sunday

Mostly cloudy with isolated flurries, 1-5 cm possible. Moderate westerly wind. Freezing levels rise to 2100 m.

Monday

Mostly cloudy with light westerly winds. Flurries possible. Freezing levels remain around 2000 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Brief periods of sun could quickly initiate natural avalanche activity.
  • Be carefull around freshly wind loaded features.
  • Wind slabs are most reactive during their formation.
  • Be alert to conditions that change with elevation and sun exposure.

Régions couvertes