Bulletin d’avalanche

Banff Yoho Kootenay

Mar 29 – 30, 2024Avalanche 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

The skiing is great!

New snow amounts over the past 24 hours range from 10cm to 30cm depending on the region and convective activity. Generally more new snow has fallen to the South.

With clear skies forecasted for Saturday, the sun could have an impact on the hazard.

The more sun, snow, and wind; the more the hazard will increase.

Problèmes avalancheux

  • Wind Slabs

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

    Wind slab may be present on ridgetop and cross-loaded features.

    Dry loose avalanches out of steep terrain and on crusts could also present issues depending on new snow amounts.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    The Feb 3 crust/facet interface is down 80-110 cm. While we have not seen these in deep snowpack areas, there have been several recent skier-triggered slabs in thinner areas east of the divide. All of the recent avalanches that initiate on this layer step down to the basal facets / ground.

  • Loose Wet

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

    Clear skies are forecasted for Saturday, and as we head into April the sun will come with more "punch". Steep solar aspects and rocky terrain will be particularly reactive.

    Recent storm snow could also settle with solar into a cohesive storm slab and become reactive on buried crusts.

Confidence

Moderate

Avalanche Summary

Friday Lake Louise reported several skier-controlled and explosive size 1 dry loose and storm slab avalanches on the March 20th crust.

East of the Divide, within the last week, there have been several size 2-3 avalanches that have all been remotely or accidentally triggered by skiers. All occurred on northerly aspects in thin sub-alpine snowpack areas with no overlying March 20 crust.

Snowpack Summary

Up to 30cm of storm snow (depending on region and convective activity) covers sun crusts on solar aspects and up to 40 cm of dry snow on shaded slopes. Below this, the March 20th crust exists everywhere except north aspects above 1800m.

Our main concern is shallow snowpack areas on northerly Alpine aspects where there is no March 20 crust. Here the Feb 3 facet / crust layer and the basal facets / depth hoar remain possible to trigger

Deeper snowpack areas have fewer concerns

Weather Summary

Friday Night: Partly cloudy, trace precip, light winds from the NW with a Low of -12°C

Saturday: Mix of sun and cloud, freezing level rising to 1600m, light winds from the West.

Saturday night and Sunday: Wind picking up to moderate from the West, freezing level rising to 1800m. Mix of sun and cloud.

Click here for more weather info.

Terrain and Travel Advice

  • Be alert to conditions that change with elevation and sun exposure.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches

Régions couvertes