Avalanche forecast

South Rockies

Dec 27 – 28, 2014Avalanche Canada
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Avalanche danger

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

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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–3
    Strong and variable winds have redistributed loose surface snow into wind slabs in lee terrain. Watch for triggering behind ridge crests and terrain breaks.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    A crust which formed in December should remain on your radar. Not much is known about its distribution in the South Rockies. However, in neighboring regions it has produced large avalanches. Dig down and test weak layers before committing to a line.

Confidence

Poor - Due to the number of field observations

Weather Forecast

A moist low pressure system will linger on Sunday bringing mostly patchy light snowfall, moderate northerly winds and freezing levels at valley bottom. By Monday a dry arctic ridge will set-up for the rest of the forecast period. With this ridge, we'll see mainly clear skies, light to moderate northeast winds and alpine temperatures around -20.

Avalanche Summary

Wind slabs to size 1.5 were observed in high elevation terrain on Friday. Strong winds on Saturday may still be blowing loose surface snow into fresh wind slabs, and reactivity may persist for a few days.

Snowpack Summary

On the surface, up to 30cm of low-density snow exists. In the alpine and at treeline, winds have been conducive to blowing this snow into wind slabs in exposed lee areas. 30 - 60 cm below the surface (more in wind affected areas) you may find a crust that may have surface hoar on top of it. The crust is reported to extend into the alpine to at least 2100 m, while the surface hoar was reported to be most reactive on shady aspects around treeline and just below, between around 1600 m and 1900 m. Where the crust exists, it may be bridging triggers from penetrating to deeper persistent weaknesses that formed earlier in the season. However, on high alpine slopes above where the rain crust formed, or in areas where rain didn't occur, facets, and/or buried surface hoar may still be susceptible to triggers.

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