Avalanche forecast

South Coast Inland

Dec 19 – 20, 2022Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low

Highlights

This is not your typical coastal mountain snowpack - it is generally facetted, weak and shallow, with a significant weakness at the bottom of the snowpack. Assess for stiff, cohesive, wind slabs on the surface, that if triggered have the potential to step down to deeper weak layers.

Avalanche problems

  • Wind Slabs

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

    Cold, Northerly winds are redistributing the recent snow into potentially reactive windslabs. With cold temperatures windslabs will likely take longer then usual to stabilize and bond to the underlaying surfaces.

    Remember that small wind slabs on the surface could scrub down to deeper weak layers in the snowpack, resulting in much bigger then expected avalanches.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1.5–3

    Weak crystals sit at the base the snowpack creating concern for large avalanches. Primarily a concern in areas were a cohesive upper snow pack exists (like wind affected slopes) and even a small avalanche could scrub down to the weak layer.

Confidence

Moderate

Avalanche Summary

No new avalanche activity has been reported over the last few days.

If you head out into the mountains, please share your photos or observations on the Mountain Information Network. Your information helps us understand local conditions!

Snowpack Summary

Recent storm snow continues to facet with current cold temperatures. These sugary crystals will be easily redistributed by the current cold, Northerly winds into drifts and stiff wind slabs.

In general, the snowpack is weak, facetted, and shallow for mid-December. Snowpack depths generally range from 80-120cm at treeline. Widespread large basal facets and even depth hoar have been reported. At the moment much of the snowpack lacks much cohesion for this weak basal snow to be an issue. However, as the upper snowpack gains cohesion, with time and more snow, this deep persistent layer will likely become more of a concern.

Weather Summary

Cold arctic air dominates the weather throughout BC this week. High uncertainty remains over the potential of snowfall starting Tuesday.

Sunday night

Clear. No precipitation. Temperatures around -25 to -30 C and generally light Northeast winds in the alpine.

Monday

A mix of sun and cloud, with no precipitation. Temperatures -20 to -25 C and light Northeast winds in the alpine.

Tuesday

A mix of sun and cloud, with no precipitation. Temperatures -20 to -25 C and light North winds in the alpine.

Wednesday

A mix of sun and cloud, with no precipitation. Temperatures -20 to -25 C and light Northeast winds.

Tuesday

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Conditions may have improved, but be mindful that deep instabilities are still present.

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