Bulletin d’avalanche

South Coast Inland

Mar 4, 2017Avalanche Canada
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Archivé · expiré 10 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

Strong SW wind and fresh snow Friday night may fuel a round of natural avalanches while most of us sleep. Light wind and snowfall on Saturday may appear picture-perfect, but the mountains are currently primed for human triggered avalanches.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–4
    A pattern of persistent slab avalanche activity recently emerged in the northern part of the region. Recreating in the mountains north of Pemberton suggests using more conservative terrain with additional caution on northerly aspects.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–3
    Strong southerly winds from Friday will continue into Friday night promoting the development of fresh sensitive wind slabs in exposed terrain.  Watch for especially deep and touchy slabs on wind loaded slopes this weekend.

Confidence

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

Weather Forecast

A deep upper trough is moving through BC this weekend. A few disturbances are expected to continue to deliver moderate precipitation into southwestern BC through Friday night. As the trough exits Saturday, snowfall is expected to cease as the freezing level drops to valley bottom. Sunday offers a break in the action before modest snowfall begins again on Monday.FRIDAY NIGHT: 5 to 15 cm of snow, strong to extreme southwest wind, freezing level at 1500m, falling throughout the night.SATURDAY: Overcast skies, freezing level near valley bottom rising to about 700m in the afternoon, moderate SW wind, 1 to 5 cm of snow. SUNDAY: Overcast skies, freezing level near valley bottom rising to about 600m in the afternoon, moderate SW wind, no significant precipitation expected. MONDAY: Overcast skies, freezing level around 500m, moderate SW wind, 1 to 5 cm of snow. Visit avalanche.ca/weather for a more detailed mountain weather forecast.

Avalanche Summary

On Thursday skiers triggered wind slabs on both northeast and southeast aspects to size 2, see this great MIN report from Thar Peak Thursday: https://bit.ly/2lFjEQL Reports from Wednesday include several natural avalanches in steep leeward alpine terrain up to Size 2.

Snowpack Summary

Much of the region received 30 to 70cm of fresh snow this week, which has been blown into deep drifts by southerly winds and is bonding poorly to facets and buried surface hoar, as well as crust on previously sun-exposed slopes. The widespread mid-February crust is below all this. In the northern part of the region, a facet/surface hoar weakness buried early February, is now down around a metre and remains reactive in snowpack tests. It is also suspected as the failure plane in at least one of two recent large persistent slab avalanches in the Hurley Pass area. In the Cascades (e.g. Coquihalla), the mid and lower snowpack are well settled and strong.

Régions couvertes