Bollettino valanghe

Cariboos

Mar 19 – 20, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

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

In sintesi

The wind is expected to be strong from the southwest. If there is more snow than the forecast 10cm available to be transported into windslabs, then the Alpine danger level may be closer to HIGH.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–4
    Recent southwest wind and new snow have developed windslabs in the alpine and at treeline. These windslabs may take a few days to settle and bond.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–4
    Cornices are very large. Forecast new snow and strong winds may cause new weak growth that may fall off naturally.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    3–7
    The mid-February weak layer of facets, surface hoar, and crusts has been buried for about six weeks. Reports of avalanches releasing on this layer are becoming less frequent. Avalanches that do release on this layer may be very large and destructive.

Confidence

Fair - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

A Pacific frontal system should move on to the coast this afternoon or evening. The front is forecast to be fast moving and should affect the interior ranges overnight Monday. Forecast snowfall amounts are 5-10 cm overnight combined with strong southerly winds. The wind is expected to shift a bit to the southwest and continue to be strong during the day on Tuesday as another 5-10 cm is expected to accumulate. Unsettled weather is forecast for the interior mountains on Wednesday as the fast moving system should have moved on to the East. On Thursday a weak low pressure system is expected to move up from south of the U.S. border spreading light to moderate precipitation mostly to the southern regions of the interior.

Avalanche Summary

Natural avalanches up to size 3.5 on northerly aspects failing down about 100-150 cm on the mid-february persistent weak layer. Avalanches releasing on this layer are becoming less frequent. Large triggers like cornice fall may initiate a release on the PWL.

Snowpack Summary

Sunny breaks on Sunday caused moist snow up to about 2400 metres on solar aspects and up to about 1500 metres on all aspects. The recent storm snow is reported to have settled and bonded in most areas. Recent cornice growth has made cornices unstable. The new snow has added to the well consolidated storm slab that overlies weak surfaces that formed early February. This interface, which lies between 1 and 2 metres below the surface, includes a widespread surface hoar instability that, depending on aspect and elevation, may exist in combination with facets or crusts. These persistent weak layers have been reactive all week and remain a concern at all elevations. The weight of new snow, near-surface avalanches, sleds, and skiers may easily trigger these deeper weaknesses creating unexpectedly large and destructive avalanches.

Regioni coperte