Avalanche forecast

South Columbia

Apr 23 – 26, 2021Avalanche Canada
View on map
Archived · expired 5 years ago

Avalanche danger

Sun
Mon
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
Open full map

Highlights

Heightened danger ratings reflect up to 30 cm of new snow forecast at upper elevations in the south of the region by Sunday. Fresh snow will be sensitive to the sun 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 - Likely
    Size
    1–2

    The south of the region may see up to 30 cm of new snow by 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

Friday night: Partly cloudy, light wind, alpine high near -3, freezing level 2000 m.

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

Sunday: 15-30 cm new snow in the south of the region, trace in the north, light southwest wind, alpine high near -4, freezing level 1700 m.

Monday: Flurries bringing up to 5 cm, moderate westerly wind, alpine high near -4, freezing level 1700 m.

Avalanche Summary

Warm temperatures last week resulted in widespread wet avalanche activity. The most notable activity was last Saturday where there was both widespread size 1-2 wet loose avalanches and a few larger and destructive (size 2.5-3.5) wet slab avalanches. The large wet slabs were mostly on south and west facing slopes. Avalanche activity has been on the decline since then with relatively cooler temperatures. A cornice fall triggered a large (size 3) slab avalanche on a north-facing alpine ridge in Glacier National Park on Tuesday.

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 15-20 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. There are no layers of concern in the snowpack, which has been melting and settling over the past week. Large cornices loom along many ridgelines.

Terrain and Travel

  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Make observations and assess conditions continually as you travel.
  • Closely monitor how the new snow is bonding to the crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Regions covered