Avalanche forecast

Purcells

Apr 22 – 23, 2021Avalanche Canada
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Avalanche danger

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

Be careful around cornices and watch for new snow forming isolated wind slabs in the alpine. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Overnight snow and wind may form isolated pockets of unstable wind slabs in the alpine.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3

    Minimize your exposure below cornices. Cornice falls are dangerous on their own and can possibly trigger avalanches on slopes below.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Small loose wet avalanches are possible in new snow at upper elevations and wet snow at lower elevations that hasn't refrozen overnight.

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

Thursday night: Partly cloudy with isolated flurries up to 10 cm in the southwest of the region, light wind, alpine temperature near -7, freezing level near valley bottom.

Friday: Mostly cloudy, light to moderate northwest wind, alpine high near -3, freezing level 1900 m.

Saturday: Flurries up to 5 cm, light wind, alpine high near -4, freezing level 1700 m.

Sunday: Around 10 cm new snow, moderate to strong southwest wind, alpine high near -3, freezing level 1700 m.

Avalanche Summary

Warm temperatures last week resulted in widespread wet avalanche activity, primarily on sun-exposed slopes. Most of the activity was size 1-2 wet loose avalanches, but a few larger and destructive wet slab avalanches were reported near the Bugaboos on Saturday and near Golden on Monday. Some large cornice falls were also observed.

The cooling trend will make wet avalanches problems less likely in the coming days, making isolated wind slabs and cornice falls the primary concern.

Snowpack Summary

The upper snowpack has undergone multiple melt-freeze cycles and is now crusty and refrozen in the cooler temperatures. Dry snow may still be found on northerly aspects above roughly 2300 m. We suspect older weak layers have gone inactive as the weather patterns over the past month have been favourable for strengthening the snowpack.

Terrain and Travel

  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.

Regions covered