Bollettino valanghe

Northwest Coastal

Dec 13, 2016Avalanche Canada
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Archiviato · scaduto 10 years ago

Pericolo valanghe

Tue
Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Apri la mappa completa

In sintesi

A weak layer of surface hoar that is now buried around a metre deep is creating a low likelihood, high consequence scenario. Continue to investigate this layer carefully.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2
    Recently formed wind slabs may remain reactive to human triggers for several days after the winds die down. Wind slabs may be present on many aspects and elevations due to strong and highly variable wind directions.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3
    A persistent weak layer of touchy surface hoar is buried 60-120 cm deep throughout the region, and may be reactive to human triggers. Smaller wind slabs may step-down to this layer resulting in large avalanches.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Tuesday: Sunny / Moderate to strong northeasterly winds / Average temperature at treeline -13 C.Wednesday: Sunny / Moderate to strong northeasterly winds / Average temperature at treeline -12 C.Thursday: Sunny / Moderate to strong northeasterly winds / Average temperature at treeline -16 C.

Avalanche Summary

On Sunday, there was a report of a size 2 natural avalanche west of Terrace. It was on a southwest aspect and it was estimated that it failed on the mid-November surface hoar layer around a metre deep. This layer may remain reactive to human triggers in isolated locations for weeks and requires continued investigation.

Snowpack Summary

Clear skies and strong outflow winds have created a variety of snow surfaces including scouring and hard wind slabs in exposed areas and up to 12 mm surface hoar formation in sheltered areas. Strong easterly winds over the past week have created wind slabs on aspects you may not expect them. Wind slabs could be present on all aspects in open areas at treeline and above. A layer of surface hoar which was buried mid-November is down 60-120 cm in many parts of the region. This layer may be reactive to human triggers in isolated locations or could be triggered by a smaller wind slab that 'steps-down' to this layer. Treeline snow depths are around 140-200 cm in the Terrace and Stewart areas, but substantially less further north. Concerns in the north are basal weaknesses that may exist in the shallower snowpack areas especially on smooth alpine features like glaciers.

Regioni coperte