Bulletin d’avalanche

Purcells

Feb 21 – 22, 2024Avalanche Canada
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Archivé · expiré 3 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible

Points saillants

A deep persistent slab problem remains where the near-surface crust is thin or absent.

Low-probability, high-consequence problems are best managed with conservative terrain choices.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Wind slabs are slowly bonding, or are getting softer and less reactive due to near-surface faceting. It is still possible for the weight of a human to trigger a small wind slab avalanche.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3.5

    A weak layer near the base of the snowpack is a concern where a thick, strong, near-surface crust does not exist. This could be at higher elevations in the alpine and in steep, rocky, open features at treeline,

Confidence

Moderate

Avalanche Summary

On Monday, natural loose dry avalanches were reported to size 1 in steep polar aspects.

Over the weekend, several wind slab and loose avalanches were reported, up to size 1.5, in steep alpine terrain, some triggered by humans, and some by the sun.

Snowpack Summary

1 to 5 cm of snow overlies wind affected surfaces in open areas and a sun crust on solar slopes.

In sheltered areas, 10 to 30 cm of settling snow sits over a frozen crust that formed in early February. This crust is generally supportive to the weight of a human below treeline, but becomes breakable around treeline, and disappears as you ascend higher into the alpine.

The midpack is generally faceted.

The bottom 15-30 cm of the snowpack consists of weak faceted grains, depth hoar, and crusts that continue to produce sporadic, large avalanches.

Weather Summary

Tuesday Night

Mostly cloudy. 0 to 5 cm of snow. 10 to 25 km/h southwest ridgetop wind. Treeline temperature around -3 °C. Freezing level rising to 1200 m.

Wednesday

Partly cloudy. 0 to 2 cm of snow. 10 to 20 km/h southwest ridgetop wind. Treeline temperature around -2 °C. Freezing level rising to 1700 m. 

Thursday

A mix of sun and cloud. 20 to 30 km/h southwest ridgetop wind. Treeline temperature around -1 °C. Freezing level rising to 1700 m.

Friday

A mix of sun and cloud. 10 to 25 km/h west ridgetop wind. Treeline temperature around 0°C. Freezing level rising to 1900 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Conditions may have improved, but be mindful that deep instabilities are still present.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.

Régions couvertes