Bulletin d’avalanche

Purcells

Nov 20 – 21, 2011Avalanche Canada
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Archivé · expiré 15 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

This bulletin is based on limited data. Local variation in conditions and danger levels are likely to exist. To produce more accurate forecasts, we need information. Please send an email to [email protected]

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Strong southerly, then north-westerly, winds have shifted snow onto downwind slopes. Some reverse loading may occur from Northeast winds in areas that still have snow available for transport.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Weak snow at the base of the snowpack will take time to gain strength. Steep or exposed terrain should be treated with suspicion. No new info so will keep this problem in for now.

Confidence

Poor - Due to limited field observations

Weather Forecast

Moderate precipitation amounts and light to moderate southwest winds are forecast for the interior during the day on Monday. The winds are then forecast to increase in the alpine with gusts to strong from the southwest overnight and into the morning Tuesday. There is a possibility that some up-slopes areas like the west monashees may see heavier than forecast precipitation amounts in the area of 20-30 cms of snow. The snow is forecast to continue through Wednesday with higher precipitation amounts forecast for the areas south of the Trans Canada Highway.

Avalanche Summary

A cycle of natural avalanche activity was observed in Quartz Creek on Sunday the 13th. Wind slabs (20cm deep) and persistent slabs (60cm deep) were observed. Persistent slabs were propagating widely and running on a weakness towards the base of the snowpack. Observations are limited to the northern Purcells so I don't know if this kind of thing is still occurring here. We have no new reports of new avalanches.

Snowpack Summary

There is significant variability in the snowpack across the region. Snowpack depth at treeline varies from around 40-130cm. Up to 50cm of snow fell late last week and over the weekend, which was redistributed by strong winds blowing first from the south and then from the north-west. A basal layer of facets was reported in the Dogtooth Range, with a weak interface between the lower facets and recent storm snow. Cold temperatures should cause continued facetting on the surface and in the basal layers.

Régions couvertes