Bollettino valanghe

Sea To Sky

Dec 5 – 6, 2012Avalanche Canada
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Archiviato · scaduto 14 years ago

Pericolo valanghe

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

In sintesi

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–5
    Fresh wind slabs can be found well below ridge crests, behind terrain features and in cross-loaded gullies in any wind-exposed terrain. Expect these deep drifts to be very touchy.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–6
    An old facet/crust combination deep in the snowpack may wake up with heavy triggers, smaller avalanches stepping down, or triggering from thin-spots, particularly on slopes with smooth ground cover.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–5
    Weaknesses within and under the recent storm snow are susceptible to human triggers, particularly in sheltered areas treeline and below, and could easily produce avalanches large enough to bury a person.

Confidence

Fair - Due to limited field observations for the entire period

Weather Forecast

Overnight and Thursday: Mostly cloudy with light precipitation overnight. Mostly dry with some sunny breaks during the day. Some western upslope areas may see 3-5 mm in the morning. Moderate westerly winds and temperatures near -10.0 in the alpine.Friday: Some light precipitation overnight. Sunny periods during the day with moderate west – southwest winds, gusty periods in the evening. Alpine temperatures continue to be about -10.0Saturday: Sunny periods with light winds and alpine temperatures about -7.0

Avalanche Summary

Some size 1.0  stiff wind slab releases in the alpine on Monday. Very strong winds during the storm stripped fetch zones and transported snow well down lee slopes.

Snowpack Summary

Treeline and alpine areas have received well over a metre of new snow since late last week with weaknesses lingering within and under this storm snow. Of particular note was preserved 8mm surface hoar found on a sheltered open slope just below treeline, which gave moderate but energetic sudden collapse results in repeated compression tests. The mid-pack seems to be fairly settled, strong, and possibly bridging instabilities that may exist deeper. However, snowpack tests continue to produce occasional hard but sudden results on the early November facet/crust combination down as deep as 200cm on leeward slopes. Furthermore, favorable slab structure for step-down fractures can contribute to the persistence of this deep weakness.

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