Bulletin d’avalanche

North Columbia

Feb 16, 2019Avalanche Canada
Voir sur la carte
Archivé · expiré 8 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

Until recently, this region was a hotspot for avalanche activity on two persistent weak layers within the snowpack. Despite the moderate hazard, a cautious approach to backcountry travel is recommended.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Wind slabs have been reported on all aspects in exposed areas. Wind slabs at treeline elevations have the potential to step down to a persistent weak layer resulting in large avalanches.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3
    There are two persistent weak layers in the snowpack, buried approximately 40 cm and 75 cm below the surface. Activity is most pronounced at treeline elevations.

Confidence

High -

Weather Forecast

FRIDAY NIGHT: Around 5 cm of low density snow expected. Mostly light winds.SATURDAY: 2-4 cm new snow. Treeline temperatures around -8C. Light northeasterly winds.SUNDAY: Flurries. Treeline temperatures around -10C. Light northeasterly winds.MONDAY: Dry, with some clear spells. Treeline temperatures around -12C. Moderate northwesterly winds.

Avalanche Summary

On Wednesday and Thursday a few size 1-1.5 wind slab avalanches were triggered naturally and by skiers mostly in the alpine on a variety of aspects. Persistent slab avalanches have tapered off, with three events noted on northeast aspects between 1200 and 1900 m from Monday and Tuesday this week but none reported on Wednesday or Thursday. However, I'd remain leery of the mid- and late-January weak layers especially at treeline elevations.

Snowpack Summary

10-15 cm of recent low density snow sitting on the surface has been blown around by strong northeasterly winds, creating reverse-loading on some slopes. There are two prominent, touchy weak layers in the snowpack that have been responsible for a several dangerous avalanches in the past 2 weeks. The upper layer was buried at the end of January and lies approximately 40 cm below the surface. The lower one was buried mid-January and lies approximately 75 cm below the surface. Both comprise a mix of surface hoar and facets and may lie on top of a sun crust on southerly aspects. Both layers are potentially reactive and in any given location, one or both could potentially exist in the snowpack. Wide propagation has been noted, meaning avalanches have the potential to be large (up to size 3). These weak layers are most prevalent at treeline and below, but may also be found in sheltered areas in the alpine.Average snow depths are approximately 300 cm. Very sporadically, failures have occurred near the base of the snowpack in or close to this region. These releases have almost all been from high alpine areas, possibly triggered close to rocky features.

Régions couvertes