Bulletin d’avalanche

South Coast

Feb 4 – 5, 2016Avalanche Canada
Voir sur la carte
Archivé · expiré 11 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

New storm slabs developing during the day on Friday. If the storm is earlier or more intense than forecast, avalanche danger may reach HIGH by Friday afternoon.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    Buried persistent weaknesses may have been destroyed in most areas, but remain cautious in high elevation terrain (particularly in the north of the region) where this problem may be lingering. New storm loading may release or step down to this layer.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    New storm slabs are expected to develop with forecast snow and strong winds.

Confidence

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

Weather Forecast

Light snow and strong southwest winds overnight with the freezing level close to 800 metres. Snow becoming heavy with strong southerly winds on Friday and freezing level around 1500 metres Snow ending overnight as the storm moves off to the east. Some sunny breaks on Saturday with moderate westerly winds and freezing levels around 1000 metres. On Sunday, a mix of sun and cloud with moderate southerly winds and freezing levels rising up to alpine elevations.

Avalanche Summary

No new avalanches reported on Wednesday. On Tuesday a skier remotely triggered a size 3.0 slab avalanche from 20 metres away that released on the early January surface hoar. This avalanche happened at 2300 metres on a south-southeast aspect in the Duffey Lake area. The fracture propagated 350 metres and ran 750 metres to the valley bottom.

Snowpack Summary

New storm slabs are forecast to develop during the day on Friday. In the south, 40-70 cm of recent storm snow sits on a widespread and generally supportive rain crust that was buried on Jan. 28. The bond to the crust appears to be fairly good but at least one notable storm snow weakness was observed 10 cm above the crust. Fresh pockets of wind slab may also form in immediate lee features. The combination of heavy storm loading, rain, and warm temperatures likely flushed out the mid-January persistent weakness in most areas in the Cascades. Further north, generally 20-40 cm of dry storm snow overlies the late-Jan rain crust below around 1800-2000 m. Above this elevation the new snow sits on settled storm snow or previously wind affected surfaces. Fresh pockets of wind slab are likely in exposed lee terrain. Where it still exists, the mid-January surface hoar layer is between 60 and 130 cm below the surface. This persistent weakness could be lingering on higher elevation slopes that did not previously avalanche and triggering remains a concern.

Régions couvertes