Avalanche forecast

Purcells

Jan 20 – 21, 2016Avalanche Canada
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Avalanche danger

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

Strong wind, warming temperatures and new snow may create new avalanche problems.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Wind slabs may be lurking behind ridges and ribs. They may be extra sensitive where they overlie a buried sun crust.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    With each successive snowfall, a slab is gradually forming above a touchy buried weakness. This could be triggered by the weight of a person, even from a distance.

Confidence

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

Weather Forecast

A Pacific front embedded in a southerly flow brings snow (5-20 cm total), strong S to SW winds and freezing levels rising to around 1500 m on Thursday and Friday. Precipitation and winds ease and temperatures drop on Saturday.For more details check out https://avalanche.ca/weather.

Avalanche Summary

On Monday, several small slabs were triggered by skiers, including three that were remotely triggered. These were either on wind-loaded features at and above treeline, or in openings at low elevations, where buried surface hoar is largest and most reactive. These events suggest that there is a very touchy interface, but in general there is not enough load above it to create destructive avalanches. This situation could very quickly change, so watch for any areas with increased loading from wind or snow, and be alert if temperature changes cause the slab to become more cohesive. On Tuesday, skiers who ventured onto a steep alpine feature in a permanently closed area within a ski area triggered a size 1.5 wind slab.

Snowpack Summary

Conditions are variable across the Purcells. Isolated wind slabs are lurking behind ridges and ribs in some areas. 15-40 cm of recent storm snow overlies a mix of surface hoar, facets, and sun crusts that were buried in early January. In many parts of the Purcells, there is not yet a cohesive slab above this interface, apart from in wind-affected areas. In the far west of the region, there may be a deeper and more consolidated slab over the touchy early January interface. Operators are still keeping an eye on a more deeply buried layer of surface hoar from December, which is now considered dormant or unreactive. In general, the mid and lower snowpack are well settled and strong.

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