Avalanche forecast

Cariboos

Nov 25 – 26, 2012Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

This bulletin is based on limited data. Local variations in conditions are likely to exist. Check out the forecasters blog for further details on interpreting early season bulletins.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    There is a variable crust that exists in the lower snowpack. Watch for triggering on unsupported terrain at higher elevations or within start zones with smooth ground cover (scree fields, glacier headwalls, slopes with snow from last year).

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–4
    Healthy snow accumulations prior to the weekend added to an ongoing storm slab problem that exists as a wind slab in some exposed areas. If solar input is strong on Monday, there may be an increase in avalanche activity on steep sun-exposed slopes.

Confidence

Poor - Due to limited field observations

Weather Forecast

Skies will be mostly clear for Monday with increasing cloud on Tuesday and a chance of light flurries on Wednesday. Ridgetop winds should be mostly light from the west/northwest switching to light from the southeast with the approach of Wednesday's system. Freezing levels should climb gradually from 700m on Monday to 1100m by Wednesday.

Avalanche Summary

Just before the weekend we received a report from the Valemount area of  a snowmobile triggering a size 2.0 avalanche that was about 70 cm deep and about 80 metres wide. The avalanche was triggered from a shallow weak area, and suspect that the weak layer was either the November crust or buried surface hoar. Any field observations are welcome at [email protected].

Snowpack Summary

Some parts of the region received over 30cms of new snow on Thursday adding to the healthy amounts that fell throughout the week. Although alpine wind data has been sparse, velocities in neighboring regions have been in the upper end of moderate. That said, I'd be highly curious about the possibility of windslabs in exposed areas. Although storm slab reactivity is still possible, a break in the snowfall over the weekend has most likely given the upper snowpack a chance to settle and gain some strength.  There may be a thin buried surface hoar layer down about 85 cm in the alpine. As well, the November rain crust now exists over 100cm down in some locations and may exist in combination with facets. This layer has shown sudden planar test results.

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