Avalanche forecast

North Columbia

Dec 16 – 17, 2020Avalanche Canada
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Avalanche danger

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

20-40 cm of new snow with southwest winds have likely formed reactive storm slabs. Choose conservative terrain and watch for signs of instability such as whumphing, cracking and recent avalanches.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    40-60 cm of snow sits above a layer of surface hoar and/or crusts. 

  • Storm Slabs

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

    20-40 cm of new snow sits on a weak layer of surface hoar. This new snow combined with southwest winds has likely created slabs that may be easy to trigger.

Confidence

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

Weather Forecast

TUESDAY NIGHT - Cloudy with flurries, 5-10 cm / southwest wind, 25-50 km/h / alpine low temperature near -8

WEDNESDAY - Mainly cloudy with isolated flurries, 5 cm / southwest wind, 20-40 km/h / alpine high temperature near -7 

THURSDAY - Flurries, 5-15 cm / southwest wind, 20-40 km/h / alpine high temperature near -7

FRIDAY - Periods of snow, 15-20 cm / southwest wind, 30-60 km/h / alpine high temperature near -7

Avalanche Summary

With 20-40 cm of new snow and moderate to strong southwest winds, human triggered avalanches are likely, especially in wind loaded areas.

Snowpack Summary

20-40 cm of snow has fallen in the region since Monday afternoon. This new snow has buried a weak layer of surface hoar in many areas. Moderate to strong southwest winds will mean that this new snow will likely form reactive slabs.

A weak layer that was buried about a week ago is now down 40-60 cm. This layer is variable and has been reported to exist as either a crust or surface hoar. In any case, it is a persistent weak layer with a significant load above it now, and it may react easily to human triggers.

Another crust that was buried in early November can be found near the base of the snowpack. There have been no recent avalanches reported on this layer, however it may be possible to trigger it from shallow, rocky terrain.

Terrain and Travel

  • Choose conservative terrain and watch for clues of instability.
  • Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Regions covered