Avalanche forecast

Cariboos

Mar 16 – 17, 2012Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
4 · High
Treeline
3 · Considerable
Below
3 · Considerable
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–5
    Recent southwest wind and new snow have developed windslabs in the alpine and at treeline. These windslabs may take a few days to settle and bond.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    3–7
    Persistent weaknesses are buried upwards of 150cm below the surface. Surprisingly large and destructive avalanches could be triggered naturally by the weight of additional snowfall, or by the energy of a person/sled.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–6
    The recent storm snow has consolidated into a cohesive slab. Extended sunny breaks may weaken the slab resulting in natural activity. Storm slab avalanches may step down to deeper weak layers.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

Unsettled conditions are expected for Saturday and Sunday. Light winds and convective snow showers are forecast to bring up to 10 cm on Saturday. Clearing overnight should turn to broken skies during the day on Sunday. There may be some clearing on Monday if a ridge of high pressure extends far enough north. If the ridge does not go far enough north, then expect cloud and scattered flurries to move in from the northwest.

Avalanche Summary

One natural size 2.0 was reported from 1800 metres on a SE aspect that was 50 cm deep on Thursday. Earlier in the week natural avalanches and natural cornice falls up to size 3.5 were reported.

Snowpack Summary

The region has received about 35 cm of new snow in the past 2 days. Recent moderate to strong winds have transported available snow into thick windslabs in the alpine and at treeline, and have added weak new growth to the large cornices in the region. The new snow has added to the well consolidated storm slab that overlies weak surfaces that formed early February. This interface, which lies between 1 and 2 metres below the surface, includes a widespread surface hoar instability that, depending on aspect an elevation, may exist in combination with facets or crusts. These persistent weak layers have been reactive all week and remain a concern at all elevations. The weight of new snow, near-surface avalanches, sleds, and skiers may easily trigger these deeper weaknesses creating unexpectedly large and destructive avalanches.

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