Bollettino valanghe

Northwest Inland

Mar 12 – 13, 2023Avalanche Canada
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Archiviato · scaduto 4 years ago

Pericolo valanghe

Tue
Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole

In sintesi

Plan your travels with aspect in mind. Wind slabs remain possible to trigger on south and west facing slopes. Watch for clearing skies - short periods of sunshine can rapidly increase reactivity on south facing/sun affected slopes.

Continue to avoid thin and rocky start zones where buried weak layers are shallow.

Problemi valanghivi

  • Wind Slabs

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

    Wind slabs remain possible to trigger in terrain features that were reverse-loaded by consistent north/east winds. Wind slabs may sit over a sun crust on south facing slopes. Watch for wind drifted snow below ridge crests and rollovers and in cross-loaded terrain.

    Look for signs of active wind transport, newer wind slabs are most reactive.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3.5

    Weak, sugary crystals at the bottom of the snowpack produced large avalanches in late February. This problem may become active again with any rapid change to the snowpack, such as heavy snowfall, warming or large impacts such as cornice falls.

Confidence

Moderate

Avalanche Summary

Recent avalanche observations have been limited to solar-triggered loose avalanches from steep south aspects.

Last week the region saw numerous natural wind slab and cornice-triggered avalanches up to size 2.

On Tuesday our field team observed a size 3 deep persistent slab avalanche near Hankin that they estimated to be around a week old. The slab propagated across the full steep, rocky feature. This has been the latest of a pattern of intermittent large deep persistent slab activity in the alpine. Observations from late February include a cornice-triggered size 2.5 at Hudson Bay and several explosive controlled size 2-3 near Ningunsaw.

Snowpack Summary

Recent wind affected snow sits over previously hard, wind affected surfaces in the alpine. Sun crust or moist snow can be found on steep solar aspects .In sheltered terrain loose soft snow may still be available for good riding conditions.

Several crusts, layers of facets, or surface hoar can be found in the top 150 cm of the snowpack, but have not shown any significant avalanche activity or snowpack test results recently.

The lower snowpack consists of weak, basal facets which may become active with any rapid change in the snowpack, such as heavy loading or dramatic warming. Avoiding thin and rocky start zones is still recommended.

Weather Summary

Saturday Night

Cloudy with isolated flurries. Moderate southeasterly wind. Freezing level below valley bottom.

Sunday

Mostly cloudy with isolated flurries. Moderate southeasterly wind. Alpine high -9 ˚C.

Monday

Mostly cloudy with light snowfall, up to 5 cm. Light to moderate southeasterly wind. Alpine high -7 ˚C.

Tuesday

Partly cloudy with moderate southwest winds. Alpine high -7 ˚C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Conditions may have improved, but be mindful that deep instabilities are still present.

Regioni coperte