Bollettino valanghe

Long Range Mountains

Feb 6 – 7, 2023Avalanche Canada
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Archiviato · scaduto 4 years ago

Pericolo valanghe

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

In sintesi

As fair weather settles in this week and inspires you to explore, be sure to start small and ease into terrain cautiously. A buried weak layer (and its potential to produce large avalanches) will remain a concern even after wind slabs begin to settle and stabilize.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    1–2

    Recent snow and strong wind have formed wind slabs in leeward terrain features. Identify wind slabs by looking for stiff or drifted snow. Typical places to find them include beneath ridge crests and roll-overs and beside protruding features on cross-loaded slopes. Wind slabs may remain triggerable by riders for several days after natural avalanche activity subsides.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Cornices have grown with the recent snow and wind. Give cornices a wide berth when travelling on or below ridges. Cornice falls can be dangerous on their own and they can trigger slab avalanches on slopes below.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    A poorly bonded layer of faceted particles sits over a slippery crust ~50-150 cm deep. It has shown reactivity in recent snowpack tests and if triggered, it has potential to produce large, destructive avalanches.

Confidence

Moderate

Avalanche Summary

We expect a widespread natural storm slab avalanche cycle to have occurred during the storm Friday and Saturday. Rider-triggered wind slab avalanches will remain likely for a few days after the storm.

Although we have not had observations of avalanches running on a buried crust, snowpack tests suggest potential for failure at this interface. Resulting avalanches would be large and destructive.

Prior to this storm, recent avalanche observations have been limited to small wind slabs and cornice falls reported by our field team.

If you're heading out into the mountains, please consider sharing your observations on the Mountain Information Network!

Snowpack Summary

5-20 cm of fresh snow blankets wind ravaged surfaces from the previous storm. Expect to find deep wind slabs on leeward aspects, and scouring on exposed windward aspects.

The mid snowpack consists of 30-100 cm of recent January snow, poorly bonded to a crusty underlying lower snowpack.

Weather Summary

Monday

5-15 cm of new snow overnight, clearing to a mix of sun and cloud. Light westerly wind. Alpine temperatures near -5 C in the morning dropping to -12 C through the day.

Tuesday

Sunny, light easterly wind, alpine high temperature around -10 C.

A quiet stretch of weather until late in the week.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Recent new snow may be hiding windslabs that were easily visible before the snow fell.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Start with simple terrain and gather information before thinking about more committing features.
  • Be especially cautious as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Regioni coperte