Bollettino valanghe

Northwest Coastal

Feb 24 – 25, 2014Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 13 years ago

Pericolo valanghe

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

In sintesi

Avalanche danger will rise on Tuesday due to rapidly rising temperatures and the presence of a significant buried persistent weak layer. Stick to low angle terrain that is not exposed to overhead avalanche paths.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–4
    Outflow winds have created touchy wind slabs in exposed lee and cross-loaded terrain at all elevations.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–5
    Rapidly rising temperatures will likely increase the probability of avalanches releasing on the buried mid February persistent weak layer. The resulting slides could be very large and destructive.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–3
    A loose wet avalanche could drag you somewhere you don't want to end up, but could also be enough mass to trigger a large slab avalanche.

Confidence

Fair

Weather Forecast

Tuesday: Mainly sunny. A strong alpine temperature inversion is likely between 1500 and 2300 m. Treeline temperatures should be near +5. Temps may remain cooler further inland. Outflow winds should ease off during the day.  Wednesday: A mix of sun and cloud. The freezing level on the coast remains near 2300 m and near surface inland. Winds are light and variable.Thursday: A mix of sun and cloud with a chance of precipitation near the coast. The freezing level on the coast remains near 2000 m and near surface inland. Winds are light and variable.

Avalanche Summary

Numerous natural and skier triggered wind slabs up to size 2 were reported on Sunday in response to the outflow winds. A few large remotely triggered slab avalanches were reported in the Shames backcountry on Saturday. These were primarily from open alpine and treeline terrain and probably released on the February persistent weakness. In addition, a size 2.5 accidentally triggered slab avalanche was reported in the northern part of the region on saturday. This slide released on basal facets in steep rocky alpine terrain.

Snowpack Summary

Strong N-SE outflow winds have resulted in reverse loading and cross loading in exposed terrain at all elevations, and have scoured exposed windward slopes. The prominent mid February persistent weakness (surface hoar, facets, crust and/or wind pressed surfaces) is down 60-100 cm in the north and 120-160 cm in the south. Snowpack tests are now giving moderate to hard "pops or drops" shears on this weakness, and several whumpfs are still being reported. Basal facets and/or depth hoar remain a concern in shallow snowpack areas in the northern part of the region. Cornices are also large and may become weak if northerly winds start to undercut them.

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