Bollettino valanghe

Kootenay Boundary

Dec 11 – 12, 2015Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 11 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

Touchy fresh wind slabs at higher elevations combined with lurking persistent weaknesses at lower elevations means you can't let your guard down this weekend.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–5
    The weakness buried early-December is becoming more stubborn to trigger, but lingering pockets of buried surface hoar may maintain touchy conditions on sheltered slopes in the northern part of the region, especially in the 1400-1800m elevation range.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–3
    New snow will likely be sensitive to human triggers, and particularly deep and weak on the leeward side of ridge crests and terrain breaks, and in wind-loaded chutes.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Saturday: Increasing cloud and snowfall throughout the day with 10-15cm possible by Sunday morning. Freezing levels in valley bottoms and light southwesterly becoming moderate to strong southerly ridgetop winds. Sunday: Another 5-10cm possible with freezing levels peaking at 1400m and moderate southerly easing to light southwesterly ridgetop winds. Monday: Mainly cloudy with light snowfall and cooler temperatures.

Avalanche Summary

Reports from Thursday include an explosives-triggered 50cm thick persistent slab avalanche running on the early-December surface hoar on a convex roll below treeline in the Monashees.

Snowpack Summary

Recent heavy rain to treeline elevations and wet snow above saturated and loaded the upper snowpack, forming a thick crust which now has up to 20-25cm of fresh snow on top (with perhaps a thin crust within it). Weaknesses linger within the recent snow as well as at deeper old snow surface interfaces, which consists of facets, surface hoar, and/or a crust at upper elevations (especially on southerly aspects). The most critical of these is surface hoar buried early December (now likely down 50-100cm), which has the potential for remote triggering, extensive releases and prolonged sensitivity to triggers. It is likely lurking in most sheltered areas treeline and below. The thick mid-November crust is just under this weakness.

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