Bollettino valanghe

South Coast

Jan 29, 2018Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 9 years ago

Pericolo valanghe

Tue
Wed
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Rain will bring loose wet avalanche problems to the fore on Monday. Thick storm slabs may continue to build at high alpine elevations.

Problemi valanghivi

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1.5–2.5
    Large amounts of recent new snow and high winds have been creating rapid cornice growth. Continuing snow and rain will destabilize cornices further.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    1–2
    Heavy snowfall and strong winds are likely to create touchy new storm slabs in the alpine over Sunday night and Monday. Ongoing heavy rain may act as a trigger for less recent storm slabs at lower elevations.

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–2.5
    Heavy rain will continue to saturate our recent storm snow and promote loose wet avalanches at all but the highest alpine elevations. This may occur naturally or with a human trigger - especially in steep terrain.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

Sunday night: Heavy rain, 40-60mm accumulation. Heavy snow accumulation possible at high alpine elevations. Strong to extreme south winds. Monday: Cloudy with continuing heavy rain below about 1600 metres. 40-50mm accumulation. 30-40 cm of new snow possible at high alpine elevations. Strong to extreme southwest winds. Freezing level to 2000 metres with alpine high temperatures around 0 to +1.Tuesday: Cloudy with continuing flurries bringing 10-20 cm of new snow. Moderate southwest winds. Freezing level to 900 metres with alpine high temperatures of -3.Wednesday: Mainly cloudy with isolated flurries and a trace of new snow. Light west winds. Freezing level to 800 metres with alpine temperatures of -4.

Avalanche Summary

Reports from Saturday included one MIN submission detailing a near miss incident involving several members of a ski touring party on Hollyburn Mountain. Two skiers were partially buried and one was fully buried in a Size 1.5 storm slab that released from steeper pitch below treeline. The remaining party members performed a rapid companion rescue and no injuries were sustained by anyone involved. Other MIN reports from the region over the past two days have shown ski cutting easily producing storm slab results at the depth of each day's accumulations.Looking forward, areas that see rain falling on dry snow are expected to undergo a natural avalanche cycle over Sunday night into Monday. Areas that experience precipitation falling as snow will see rapid formation of touchy new storm slabs over the same time period.

Snowpack Summary

Heavy rainfall is set to soak the upper snowpack at most elevations over Sunday night and Monday. High alpine elevations in areas like Sky Pilot and the Chehalis Range may see thick new storm slabs develop over the same time period. Below these variable surface conditions, storm snow totals from the past week have reached 110-180 cm and strong southerly ridgetop winds during the storm have been redistibuting each day's snow into storm slabs at all elevations. The touchiest conditions will be likely to exist in exposed, higher elevation terrain, however heavy rain may also destabilize more recent storm slabs at lower elevations and will certainly promote loose wet avalanches in steeper terrain. The crust that exists beneath all our recent snow accumulations is likely to have now formed a solid bond to the overlying snow.

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