Bulletin d’avalanche

Lizard-Flathead

Mar 14 – 15, 2017Avalanche Canada
Voir sur la carte
Archivé · expiré 10 years ago

Danger d’avalanche

Thu
Fri
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
Ouvrir la carte complète

Points saillants

High freezing levels overnight with continued stormy weather will keep avalanche danger elevated.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2
    Cornices are huge and are ripe for triggering with the warm weather. Cornice falls may trigger larger persistent slab avalanches.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2
    Storm slabs are expected to continue to develop due to forecast new snow and wind. Loose wet avalanches may be a problem at lower elevations.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–4
    Storm loading and warming may increase the likelihood of triggering large deep persistent slab avalanches. Concerns include basal facets in alpine terrain and a variety of crust and facet interfaces about a metre deep.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

Overnight: Freezing level remaining above 2000 metres, combined with strong southwest winds, and 5-10 mm of precipitation. Wednesday: Freezing level around 2000 metres, combined with moderate-strong southwest winds, and 5-10 mm of precipitation. Thursday: Freezing levels dropping down to at least 1500 metres, moderate southwest winds, and a chance of sunny periods. Friday: Freezing down to valley bottoms, light southwest winds, and mostly sunny with strong solar radiation.

Avalanche Summary

Natural avalanches up to size 2.0 were reported on Tuesday. Observations were limited by poor visibility and travel conditions.

Snowpack Summary

A warm wet storm will form fresh slabs at higher elevations while rain will fall below treeline. Strong winds will load lee features and continue to grow large cornices on alpine ridges. March has delivered regular storms with roughly 80-120 cm of snow sitting above crust and facet interfaces from February. Little is known about the distribution and reactivity of these interfaces. Isolated basal facets still exist in shallow snowpack areas and can produce destructive full-depth avalanches. Possible triggers for these deeper weak layers include cornice falls, rapid warming, or strong solar radiation.

Régions couvertes