Bollettino valanghe

Kootenay Boundary

Mar 10 – 11, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

Mon
Tue
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Apri la mappa completa

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–4
    Generally lurking below ridge crests, behind terrain breaks, and in gullies. Wind slabs are touchy and likely to stay that way through the weekend with forecasted strong SW winds.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–6
    Large, destructive & unmanageable avalanches remain sensitive to natural and human triggering this weekend. Stay conservative with terrain choices and don't let your lust for powder riding lure you into a potentially deadly situation.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–3
    10 - 20 cm of snowfall is expected by the time skies clear Monday AM. Storm slabs will be sensitive to human triggering & may step down creating large avalanches. This problem will be exacerbated on convex & unsupported features.

Confidence

Fair - Timing of incoming weather is uncertain on Monday

Weather Forecast

Saturday Night: I expect light snowfall above 1300m Saturday night with freezing levels dropping down to about 1400 m by Sunday morning. Ridge top winds should be strong overnight, with very little wind below treeline. Sunday: Freezing levels stick around 1500m for most of the day, dropping to the surface with the passage of the cold front Sunday night. I expect 10 - 20 cm of snow during the day Sunday above 1300m. Winds remain strong & steady out of the SW at ridge top. Monday morning offers brief respite from the precip and warmth. Freezing levels creep up to 1500m after lunch Monday ahead of a pacific bomb which is forecast to bring 20 -40 cm in combination with extreme SW winds beginning Monday evening, continuing through Tuesday afternoon.

Avalanche Summary

No activity to report from Friday. I've left the observations from Thursday below to shine some light on the sometimes spooky nature of the buried surface hoar problem:From Friday:Several natural avalanches were reported Thursday to size 3. One noteworthy event was a size 2 avalanche that was triggered by cornice fall. The size 2 ran 50m before triggering a size 3 avalanche in lower angle terrain. The crown was reported to be 200cm in depth, failing on the Feb. 08 SH. One reported avalanche was remote triggered from 20m away on a 35 degree slope.

Snowpack Summary

Field reports indicate that a few wet cm's of snow fell Friday night landing on surface hoar, 2-6mm on north aspects and a 2cm sun crust on solar aspects. Moist snow was found Friday to 1800m, I suspect there was little change Saturday. The leap year SH is now down around 40 - 50 cm and is failing as a resistant planar shear in snowpack tests. The early February surface hoar is down 80 - 140cm, snowpack tests show moderate to hard forces generating sudden planar shears on this layer.

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