Bollettino valanghe

South Rockies

Mar 12 – 13, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

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

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2–6
    Wind slabs may be lurking behind ridges and terrain breaks.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    3–7
    A persistent weak layer around 1m deep has the potential to produce large and dangerous avalanches. It could be triggered by the weight of a person, remotely or in surprisingly mellow terrain. It is tricky to manage this problem, so be conservative.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    2–6
    Storm slabs are building deeper with each successive weather system. Loose sluffs are also a possibility in steep terrain. Storm slabs and sluffs could step down to a persistent weak layer, creating destructive avalanches.

Confidence

Fair - Due to limited field observations

Weather Forecast

Tuesday: Moderate (locally heavy) snowfall associated with a front. Moderate south-westerly winds. Freezing level gradually lowering to near valley floor. Winds turning westerly and decreasing. Wednesday: Cool and showery weather. Freezing level near valley floor. Thursday: Moderate (locally heavy) snow. Freezing level rising to 1500m. Strong south-westerly winds.

Avalanche Summary

On Monday, skiers triggered size 1-1.5 soft slabs in steep terrain. A widespread natural avalanche cycle occurred up to size 3 in response to very warm temperatures and loading of start zones by strong winds on Friday and Saturday. Video footage here: https://bit.ly/yR4E8r . On Friday, a snowmobiler was killed in a size 3 slab on a south-west aspect at treeline in the Corbin Creek area. Over the last week, there were several reports from in or near the region of near misses, including a snowmobiler who triggered an avalanche and was buried for around 30 minutes, remote-triggered avalanches, and slab avalanches running into unusually low-angled terrain.

Snowpack Summary

Storm snow continues to build up. South-westerly winds are likely to have created wind slabs behind ridges and terrain breaks. The mid February surface hoar layer in the upper snowpack is most prevalent in the west and south of the region, particularly in the Flathead. Recent snowpack tests, as well as rider-triggered avalanches, on this weak layer indicate that it still has the potential to be triggered in many areas, resulting in a large avalanche. Remote-triggering, triggering from below and triggering on low-angled terrain are also concerns. Basal facets may still exist, particularly in shallower snowpack areas with steep, rocky start zones. Cornices have grown large and threaten slopes below. Conditions are variable across the region.

Regioni coperte