Avalanche forecast

South Rockies

Dec 24, 2017Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

The best riding is in sheltered areas with low density snow, but watch for shooting cracks and whumpfing sounds as indicators of a developing persistent slab problem.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Strong winds on Saturday night are expected to blow around the low density snow and form fresh wind slabs on the downwind sides of ridges and gullies.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    A weak layer 40-80 cm below the surface has the potential to produce surprising avalanches. Triggering this layer is most likely in areas with stiffer snow on sheltered slopes. Read more about this problem in the forecasters' blog (here).

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

SUNDAY: Sunny with increasing clouds and light flurries overnight, gusty northwest winds, treeline temperatures around -18 C.MONDAY: Mix of sun and cloud, light northwest winds, treeline temperatures around -22 C.TUESDAY: Mostly sunny, strong northwest winds, treeline temperatures around -20 C.

Avalanche Summary

Some small natural dry loose avalanches were reported in steep alpine terrain on Saturday. Some larger slab avalanches were triggered with explosives immediately after last week's storm on Friday (up to size 2).

Snowpack Summary

Cold temperatures are preserving fresh snow from the past week, with up to 80 cm in southern and eastern parts of the region and 50 cm in the Elk Valley. The snow has been deposited into harder wind slabs in exposed terrain, but remains low density in sheltered areas.The main question in the snowpack surrounds the layer sitting beneath the new snow. The layer includes old crusts, wind scoured surfaces, and large feathery surface hoar crystals in sheltered terrain at and below treeline. The distribution of the layer, as well as the properties of the snow above it, is highly variable. The most suspect areas are where the wind has formed a stiff slab above this layer and on slopes with preserved surface hoar.Two crusts that were buried near the end of November can be found lower in the snowpack. A third crust from the end of October exists near the base of the snowpack. Recent testing on these crusts have not produced significant results.

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