Avalanche forecast

Purcells

Nov 16 – 17, 2011Avalanche Canada
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Archived · expired 15 years ago

Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

We have very little information from this region. If you have been in the mountains, send us an email: [email protected] and let us know what you saw.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Old windslabs still may be a problem, I don't have enough new information to be sure. Some new windslabs may form Wednesday night, especially if snowfall and winds are higher than forecast.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    I have no new information but I'm calling this a persistent slab problem for now. These take time take time to gain strength. Until we know more, steep or exposed terrain should be treated with suspicion.

Confidence

Fair - Due to limited field observations

Weather Forecast

A fast moving storm coming through the Columbias tonight will likely be much less intense in the Purcells. While there's some uncertainty, I'm guessing favoured areas will see 10cm at most overnight Wednesday and only light snow or flurries by Thursday morning. Winds will probably be moderate to strong and variable

Avalanche Summary

A cycle of natural avalanche activity was observed in Quartz Creek on Sunday. 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. Avalanche activity may pick up a bit if winds and new snow arrive, more so if the forecast is wrong and more snow falls rather than less.

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. Observations are limited. New snow and wind are in the forecast although not as much as in the Columbias to the west. Some new windslab formation is possible, especially if the actual amount of snow is more than what the forecast calls for.

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