Bollettino valanghe

Purcells

Mar 17 – 18, 2016Avalanche Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

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

In sintesi

Solar radiation and increasing freezing levels will increase natural avalanche activity. Avoid slopes with overhead exposure where falling cornices could trigger large avalanches.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–5
    Daytime warming and solar radiation will promote large cornice failures which could, in turn, trigger a large avalanche on the slope below.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    3–5
    The late February layer is becoming less likely to trigger, but it continues to surprise riders with large avalanches. I'd aim for well-supported slopes without convexities, and I'd be increasingly cautious as solar radiation comes into play.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–3
    As the sun comes out, surface avalanche conditions will include a mix of wind slabs in high elevation lee terrain, and pushy loose wet activity on steep, sun-exposed slopes. Loose wet avalanches may also trigger deep and destructive slab avalanches.

Confidence

High

Weather Forecast

The ridge over the province begins to break down on Friday with increasing clouds on Saturday and perhaps some flurries on Sunday.  Expect winds to be generally light and southerly.  The BIG news is the increasing freezing levels on Sunday(~2200m).

Avalanche Summary

On Wednesday, a few natural and explosive triggered slab avalanches to size 2.5 were reported on northerly aspects in the alpine. Solar radiation and increasing freezing levels will be the main driver of natural avalanche activity in the coming days.

Snowpack Summary

At ridgetop, cornices are huge and could be become increasingly touchy with forecast solar radiation. Sunny skies have likely promoted a melt-freeze cycle on sun-exposed slopes. 40-80 cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layer, which was buried late February, seems variably reactive. In other words, it's still really touchy in some places while in other places it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. I'd continue to be suspicious of steep, unsupported features at treeline and in the alpine as this layer has the potential for large avalanches. Deeper weak layers from mid-February and early January are now down 50-90cm and 70-120cm respectively. Triggering an avalanche on either of these layers has become unlikely but either still has the isolated potential to produce very large avalanches with a heavy trigger or significant warming.

Regioni coperte