Avalanche forecast

South Columbia

Nov 27 – 28, 2015Avalanche Canada
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Avalanche danger

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

Rising temperatures in the alpine may change the snowpack dramatically, especially on solar aspects. Forecasters are working with little information this early in the season. Share your observations through the Mountain Information Network. MIN

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Wind slabs are still lurking out there, in places you might not expect them. Reverse loading from northerly winds have built slabs on south aspects .

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Rising temperatures on solar aspects may trigger "snowballing" in steep alpine terrain, with the possibility of loose wet avalanches being triggered at treeline as well

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–5
    There is concern about the potential to trigger a deep instability in shallow snowpack areas that may have facetted snow from earlier in the season. Mostly on northerly aspects.

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

An arctic high continues to dominate the weather pattern over western Canada and is not forecast to move out of the area until Tuesday or Wednesday next week.  In the meantime, an above-freezing layer (AFL) of air will pass through the region between 1500 and 3000m bringing temperatures in that elevation band to as high as +5°c., especially on solar aspects.   Arctic air pooling in the valley bottoms will keep the temperatures well below freezing until the next storm system flushes out the cold air

Avalanche Summary

We've received a few reports of avalanche activity from operators that include relatively large (size 2.5) avalanches triggered by explosives, as well as a number of large natural avalanche that happened a few days days ago. Yesterday there were reports of small-loose avalanches believed to have run on the Nov 23rd surface hoar.

Snowpack Summary

The snowpack has been described by some observers as "extremely variable", with wind effect in all open alpine areas from the Northerly winds after the last storm. Surface hoar is widespread and observed to 4mm in sheltered locations, while windward slopes have been scoured down to bare rock in other places. Cold arctic air and temps down to -20 in some areas are promoting surface facetting. The above-freezing-layer now passing through the region could dramatically alter the snowpack.

Regions covered