Bollettino valanghe

South Rockies

Jan 19 – 20, 2012Avalanche Canada
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Archiviato · scaduto 15 years ago

Pericolo valanghe

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

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–5
    Wind slabs have formed mainly on east aspects. These could be triggered by the weight of a person, sled or cornice fall.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–6
    A buried surface hoar layer in the top metre of the snowpack continues to be a concern. Although it has become stubborn to trigger, the consequences are high. It's most likely to be triggered from shallow rocky areas on a slope, or by a large load.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–4
    Storm slabs may be triggered easily by the weight of a person. Be especially cautious on steep or convex terrain. Storm slab problems are likely to increase with forecast warming on late Friday/Saturday.

Snowpack Summary

40-60cm recent snow has formed soft slabs over a crust/facet/surface hoar combo. In sheltered areas, fast-moving sluffs also remain a concern. Forecast warming on late Friday/Saturday likely to create a more widespread storm slab problem.Deeper in the snowpack, a surface hoar layer buried in early December remains a concern, as avalanches triggered on this layer would be destructive. However, information is limited about its current reactivity. From preliminary observations, the rapid storm snow load on Tuesday did not cause any releases on this layer. Facets sandwiched between two firm layers in the top metre of the snowpack are being monitored in the south-east.

Confidence

Fair - Timing of incoming weather is uncertain on Friday

Weather Forecast

Friday: Light snow, becoming moderate to heavy by Friday afternoon. Expect enhanced snow fall in the west and less further east. Freezing level may slowly rise by afternoon. Winds increasing to strong westerlies by afternoon.Saturday: Moderate to heavy snow continuing (again, drier further east). Freezing level rising briefly to around 1000m on Saturday morning. Westerly winds.Sunday: Light snow. Freezing level valley floor.

Avalanche Summary

Skiers easily triggered size 1 slabs in both the Flathead and South of Crowsnest regions on Thursday. In the Flathead, these were running on a crust/facet/surface hoar combo below the storm snow (about 50-60cm deep). A skier remotely triggered a size 1 slab on a NE aspect at 2300m from 20m away. A widespread natural avalanche cycle occurred in the Elk Valley on Tuesday/ Tuesday night, with numerous slabs up to size 3 releasing in the alpine on mainly east-facing slopes. Initial reports suggest that these released up to 2m deep on wind-loaded slopes. South of the Crowsnest, a few size 1-2 slabs were reported during the storm.

Regioni coperte