Bollettino valanghe

Northwest Coastal

Mar 21 – 22, 2013Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 14 years ago

Pericolo valanghe

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

In sintesi

Avalanche danger may spike on slopes receiving direct sun. Avoid travelling on or underneath sun-baked terrain.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–4
    Watch for wind slabs behind ridges and ribs and in cross-loaded gullies. Oscillating winds have left slabs on a variety of slopes.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–6
    Cornices are large and unstable, especially when temperatures become warm or the sun is out. A cornice fall could trigger a large slab avalanche on the slope below.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–7
    A volatile layer of buried surface hoar around 60 cm below the surface can be triggered from a distance, propagate across large distances and create surprisingly large avalanches.

Confidence

Fair - Timing or intensity of solar radiation is uncertain for the entire period

Weather Forecast

Friday: No snow. Light N winds. Alpine temperature near -7.Saturday: No snow. Light winds. Alpine temperature near -6.Sunday: Light snow. Light winds. Alpine temperature near -10.

Avalanche Summary

On Wednesday, a skier-remote cornice failure released a size 2 slab on a NW aspect. A skier-remote size 1.5 slab failed on the March 9th surface hoar layer down around 50 cm. Numerous other skier-remote (from up to 800 m away) avalanches of size 2-2.5 also failed just to the NE of the forecast region, on the same layer. A very large (size 3.5) avalanche was triggered in Cherry Bowl in the Shames backcountry on Sunday. Click here for a full report. These slides illustrate the ongoing potential for surprising, deep and destructive releases.

Snowpack Summary

30-60 cm of recent storm snow rests on a variety of old snow surfaces, including crusts, previous wind slabs and surface hoar. Warmer temperatures and recent strong winds have now set this new snow into a reactive slab, with wind slabs building in exposed areas on a variety of aspects. The surface hoar (buried March 9th) is reported to be well-developed and fairly widespread, mainly at treeline and alpine elevations. Recent snowpack tests have produced sudden failures (pops/drops) with moderate loading force at this interface. Whumfing and remote-triggering of avalanches indicate that this layer remains volatile. A second surface hoar layer, buried on March 18, is also problematic in some areas. The mid snowpack is generally well settled and strong. Cornices are large and untrustworthy, especially when the sun is out.

Regioni coperte