Avalanche forecast

Cariboos

Feb 25 – 26, 2012Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    2–6
    Strong winds have created deep and weak wind slabs on a variety of aspects. These are sitting on several persistent weaknesses in the upper snowpack and could create destructive avalanches.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    3–7
    Cornices have grown large and weak and may fail naturally, potentially triggering the slope below and creating a very large and destructive avalanche.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    2–6
    Up to 1m of settling storm snow overlies several weaknesses including surface hoar and a sun crust. It may be possible to trigger avalanches in surprisingly low-angled terrain.

Weather Forecast

Sunday: Gradually cooling temperatures and clearing skies as a ridge of high pressure approaches. A few flurries. Light northerly winds. Freezing level valley floor.Monday: Clear with valley cloud. No precipitation. Light westerly winds. Remaining cold.Tuesday: Flurries on western slopes. Light-moderate south-westerly winds. Becoming slightly milder.

Avalanche Summary

A natural avalanche cycle occurred on Wednesday, Thursday and Friday in most areas. Slab avalanches were reported up to size 3 on all aspects and at all elevations. There were also several recent reports of skier triggered avalanches and remotely triggered avalanches up to size 2, and a size 2 snowmobile triggered avalanche near Blue River. The weight of a person will continue to have the potential to trigger large avalanches for the next couple of days.

Snowpack Summary

Strong and variable winds have created deep wind slabs on a variety of aspects at all elevations. A further 20-30cm brings storm snow totals to 60-110cm, which has now settled into a cohesive slab above the Feb 16. surface hoar layer and the Feb. 9 weakness, which includes surface hoar and/or a crust. This Feb 9 surface hoar layer may be widespread in some areas, while others have reported it being confined to shady aspects at treeline and in the alpine. A melt-freeze crust can be found down 60-90cm on solar aspects at all elevations, and on all aspects below about 1600m. In some areas this melt-freeze crust has facets above or below it. Snowpack tests on these layers have generally given easy to moderate "pops or drops" results. There is potential for easy triggering and very wide propagation. There is some concern that large loads like cornices may trigger the Jan. 20th facet layer. Some shallow snowpack areas may continue to have a weak layer of basal facets near the ground.

Regions covered