Bollettino valanghe

Northwest Coastal

Jan 4 – 5, 2013Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 14 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–5
    Storm snow is bonding poorly with buried surface hoar, creating a very touchy storm slab problem.  A person may trigger large avalanches easily, or even from a distance. Wind slabs are also likely to be found behind ridges, ribs and gully walls.

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday: Moderate SW winds. Alpine temperature -5. Around 5-10 cm snow.Sunday: Light to moderate SW winds. Alpine temperature -5. No precipitation.Monday: Light SW winds. Alpine temperature -7.  Very light snow.

Avalanche Summary

A cycle of natural and human-triggered (including remotely-triggered and helicopter-remote) avalanches of up to size 2.5 was observed across the region. Storm snow is propagating easily on buried surface hoar. Near Bear Pass, several wind slabs failed naturally on north aspects, possibly failing on facets. Skiers were witnessed going for rides in the Shames Backcountry, highlighting the surprising reactivity of the snowpack.

Snowpack Summary

20-60cm of recent storm snow is bonding poorly, with very touchy reactivity on buried surface hoar, especially near Terrace. This layer is being triggered naturally or remotely and propagating widely. Recent strong southwesterly to southeasterly winds have also set up wind slabs in many exposed lee areas. There are two surface hoar layers in the upper snowpack. The upper one formed at the end of December and is buried approximately 30 cm below the surface. This one is particularly reactive at present. The lower one formed at the beginning of December and is buried approximately 90 cm below the surface. Hard, planar compression tests have been reported on this layer. Near the base of the snowpack, a crust/facet layer continues to give hard, sudden results to no results in snowpack tests. This weakness is unlikely to be triggered by a single person, but it remains possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point.

Regioni coperte