Avalanche forecast

Purcells

Apr 23 – 26, 2021Avalanche Canada
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Avalanche danger

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

Heightened danger ratings reflect ~20 cm of new snow forecast to fall at upper elevations in the south of the region by Sunday. Fresh snow will be sensitive to solar triggering on Monday. This is the last forecast of the season. Thanks for the great winter and play safe!

Avalanche problems

  • 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.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Around 20 cm of new snow is forecast to fall in the south of the region by the end of the day Sunday. Fresh storm slabs may be reactive on the widespread crust and in wind loaded pockets. Fresh snow will also be prone to solar-triggered loose dry avalanche activity when the sun comes out on Monday.

Confidence

Moderate - Uncertainty is due to the track & intensity of the incoming weather system.

Weather Forecast

Local precipitation enhancements in the south of the region may accumulate up to 30 cm by Sunday.

Friday night: Mostly cloudy, light to moderate northwest wind, alpine high near -5, freezing level 1000 m.

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

Sunday: 5-15 cm new snow, moderate southwest wind, alpine high near -4, freezing level 1700 m.

Monday: Overnight flurries bringing up to 5 cm, then a mix of sun and cloud. Moderate to strong westerly wind, alpine high near -4, freezing level 2000 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.

Looking forward, we may see some storm slab activity in the new snow on Sunday and solar triggered loose snow avalanches will be likely on Monday.

Snowpack Summary

In the south of the region, up to 30 cm of new snow is forecast to fall by Sunday, while the north may see a light dusting. The new snow falls over a thick surface crust. 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 2400 m. We suspect older weak layers have gone inactive as the weather patterns over the past month have been favorable for strengthening the snowpack.

Terrain and Travel

  • Make observations and assess conditions continually as you travel.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.

Regions covered