Bulletin d’avalanche

Sea To Sky

Feb 4 – 5, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

New storm slabs developing during the day on Friday. If the storm is earlier or more intense than forecast, avalanche danger may reach HIGH by Friday afternoon.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Cornices may experience rapid growth due to the forecast storm. New growth may be fragile and fall off naturally.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Storm slabs developing during the day with forecast new snow and strong winds.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Light snow and strong southwest winds overnight with the freezing level close to 800 metres. Snow becoming heavy (20-30 cm in 12 hours) with strong to extreme southerly winds on Friday and freezing level around 1200 metres. Another 10-15 cm by Saturday morning as the storm moves to the east and cooler air brings the freezing level back down to 800 metres with moderate westerly winds. Some sunny breaks on Sunday as a ridge of high pressure moves over the south of the province, resulting in light southerly winds and freezing levels rising up into alpine elevations.

Avalanche Summary

No new avalanches reported on Wednesday. I suspect that strong winds and new snow are developing storm slabs in the alpine and at treeline. Storm slabs should continue to develop during the day on Friday and may start to release naturally sometime late Friday or Saturday morning depending on the timing of the new storm.

Snowpack Summary

There is a new storm slab developing; the following is the snowpack structure below the forecast new storm snow. Up to 50 cm of dry new snow sits on 60-80 cm of moist settled snow from last week's warm storm system, or a rain crust below around 1800 m. Expect to find pockets of fresh wind slab in exposed lee terrain and the potential for loose dry avalanches on steep open slopes. Cornices are also becoming large and potentially weak. Where it still exists, the mid-January surface hoar layer may be found between 100 and 180 cm below the surface. The combination of heavy storm loading and warm temperatures has likely flushed out this weak layer in most areas. However, there is still some uncertainty regarding the sensitivity and distribution of this persistent avalanche problem, especially at high elevations in the north of the region where it remains reactive in snowpack tests (hard to initiate but sudden "pops" results).

Régions couvertes