Bollettino valanghe

Purcells

Apr 1 – 2, 2016Avalanche Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

Sun
Mon
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Apri la mappa completa

In sintesi

Special Public Avalanche Warning extended for this region. Continued very warm temperatures with little overnight freeze coupled with strong solar radiation will increase the avalanche danger to HIGH in the alpine during the hottest part of the day.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    3–6
    Continued high freezing levels and very warm daytime temperatures are very likely to result in natural cornice falls. Large cornice falls may trigger buried weak layers resulting in very large avalanches.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    3–6
    Continued warm and sunny weather may add enough heat to the snowpack to “wake-up” persistent weak layers buried in the snowpack. Rapid warming of the winter snowpack can result in deeply buried weak layers propagating very large avalanches.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–4
    Forecast high freezing levels and very warm daytime temperatures may break down surface crusts early and result in loose wet avalanches from steep solar aspects. Wet slab avalanches are possible if loose snow propagates on a buried crust.

Avalanche Summary

On Thursday, solar radiation continued to result in natural cornice falls up to size 2.5 and loose wet avalanches up to size 2.0. On Wednesday, slab and loose snow avalanches were reported up to size 2 on a variety of aspects, mostly triggered by cornices or solar radiation. On Tuesday numerous loose wet avalanches up to size 2.0 were reported, and one of these loose wet slides stepped down to a buried crust down 50 cm and resulted in a size 2.5 on a steep east aspect at 2200 metres.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

The ridge of high pressure that is responsible for the clear skies and very warm temperatures is slowly starting to move eastward. Freezing levels should drop a bit, but will remain above 2500 metres overnight and morning sun should quickly break down any crusts that develop. High cloud is expected to move into the interior ranges by Saturday afternoon. Moderate westerly winds on Saturday night combined with light precipitation may not drop freezing levels more than a few hundred metres, and may inhibit crust formation overnight. Sunday should be mostly sunny with light winds and freezing levels at 2500 metres. Freezing levels should begin to drop by Monday morning, when moderate southwest winds and precipitation move inland from the coast.

Snowpack Summary

Forecast warming and strong solar is expected to result in loose wet avalanches on sun exposed aspects at all elevations. This warming trend may start to affect deeper snowpack layers each day. Surface crusts may break down early, and persistent weak layers may fail if the warming reaches their fragile structure. The late February surface hoar/crust layer is down 40-90 cm. This layer may continue to react to human triggers during periods of strong solar radiation and high daytime temperatures. Loose wet avalanches in motion, or cornice falls may step down to deeply buried weak layers. Cornices continue to be described as large and fragile, and may fail with forecast warming and strong sunshine this week. Conservative terrain without overhead hazard is a good strategy for avoiding the persistent slab problem.

Regioni coperte