Bulletin d’avalanche

Northwest Inland

Feb 3 – 4, 2015Avalanche Canada
Voir sur la carte
Archivé · expiré 12 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

Recent snowfall and strong winds are creating new problems. Solar inputs on Wednesday may elevate your local hazard. Assess the stability in your riding area before committing to avalanche terrain.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    The late-Jan crust is down 60-80cm and may still be reactive in some areas. In the mid-pack there are older persistent weak layers but these have generally stabilized. Extra caution is required in thinner snowpack areas, especially the north.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    20-30cm of recent storm snow may be settling into a widespread storm slab. In exposed terrain, new wind slabs can be expected. Loose sluffing from steep terrain may also be a concern.  Use extra caution on sun exposed slopes.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    3–6
    Although less likely to trigger, recent avalanche activity suggests weak layers buried at the beginning of the winter should still be our radar, especially in the north of the region.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A ridge of high pressure should keep the NW Inland mainly dry on Wednesday. A mix of sun and cloud is expected with freezing levels at valley bottom and moderate alpine winds from the SW-W. On Thursday, sub-tropical moisture will mix with arctic air resulting in moderate snowfall. Freezing levels should remain at valley bottom and alpine winds will become strong-to-extreme. Conditions on Friday should be much the same with moderate-to-heavy snowfall, valley bottom freezing levels, and strong-to-extreme winds.

Avalanche Summary

On Monday, natural and human-triggered avalanches size 1 to 1.5 were reported in the south of the region. These were 20-30cm thick in sheltered areas and 30cm+ in wind loaded features. Sluffing from steep terrain was also reported. On Wednesday, natural avalanches are possible on sun exposed slopes or recently wind-loaded features. Skier-triggering is likely in wind loaded features and areas where the recent snowfall is settling into a cohesive slab.

Snowpack Summary

20-30cm of new snow has fallen in the last couple days. Strong winds have redistributed this snow in exposed terrain forming winds slabs in leeward features and stripping exposed slopes. The late-January crust is typically down 60-80cm in the south of the region and probably around half this depth in the north. Tests are indicating that this interface is generally well bonded but isolated avalanches have been reported to have released on this layer recently. The mid-January rain crust and/or surface hoar layer is down over 1m in the south and has generally become inactive. It may still be a concern in thinner snowpack areas, at higher elevations, and in the far north of the region. Near the base of the snowpack is a crust-facet combination buried in November. This deep persistent weakness was recently reactive and may still be touchy in the far north of the region. Wherever you are, I'd be cautious of this deep and potentially destructive layer. Possible triggers include thin spot triggering in high elevation terrain, a cornice fall, or a smaller avalanche stepping down.

Régions couvertes