Bollettino valanghe

Kootenay Boundary

Jan 16 – 17, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

Wed
Thu
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–4
    Fresh weak wind slabs are lurking below ridgecrests, behind terrain features and in cross-loaded gullies.
  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–5
    Weak surface hoar is primarily a concern on big unsupported sheltered glades on east through north aspects. Basal depth hoar and facets are a concern on slopes with shallow and variable snowpack depths, especially near ridges and summits.

Confidence

Poor - Track of incoming weather is uncertain on Wednesday

Weather Forecast

Tuesday: Continued isolated flurries with freezing levels in valley bottoms and strong westerly alpine winds. There is high uncertainty with the weather for Wednesday and Thursday. Some forecast models are calling for moderate snowfall while others are calling for almost none. It all has to do with track of a frontal system that's primarily heading south of the region. If heavy loading from snow or wind does occur, then expect avalanche danger to increase.

Avalanche Summary

Reports from yesterday include isolated Size 1 human triggered wind slab avalanche on a east-northeast facing alpine slope near the ridgecrest, generally sluggish and slow moving. Low density storm snow is sluffing readily in steep terrain with a natural cycle overnight Saturday. In some cases they're entraining considerable mass and reaching up to Size 2.

Snowpack Summary

Snow flurries have maintained a fresh snow supply for wind slab development and cornice growth, but remains fluffy and cohesionless in most sheltered areas. Surface hoar and/or faceted snow, with an associated crust making it especially touchy on sun-exposed slopes, was buried last week and is now down 15-25cm. Below that a thin melt/freeze crust buried early-January can be found as high as 1900m, and some areas are reporting surface hoar . The mid-December surface hoar/facet persistent weakness, now down 50-120cm, remains a concern with heavy triggers in thin slab areas. Basal facets remain concern in shallow snowpack areas especially with heavy triggers in thin spots, and weaknesses in the slab above create the potential for step-down avalanches.

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