Avalanche forecast

South Columbia

Dec 2 – 3, 2015Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Storm snow is falling on a variety of nasty weak layers. As new snow, wind and potential warming combine over the next few days an avalanche cycle is expected to ensue. Pay attention out there, conditions could get real this weekend.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–3
    Previously strong north winds formed wind slabs that extend from treeline to just below ridge crest. Most of these wind slabs are probably old, tired and hard to trigger, but there may be a few that remain sensitive to human triggering.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    A few nasty weak layers are being buried by the new snow.  Storm slabs should not be much of a problem yet, but this problem is expected to become very touchy as the new snow combines with wind and potential warming this weekend.

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain on Saturday

Weather Forecast

A series of rather warm systems are stacked up off the Coast of BC. These storms are expected to pummel the coast bringing significant precipitation and wind. Its expected that some of this energy will spill over into the Mountains of the South Columbia, but its impossible to say just how much. Thursday should deliver a few centimeters of snow during the day and winds are expected to be strong out of the SW as the freezing level climbs towards 1700m. Thursday night should usher in a few more centimeters as the freezing level hovers around 1700m. Another few centimeters are expected Friday with the freezing level around 1500m. Saturday and Saturday night may offer more juicy systems, but its too far out to say what the impact will be, the pattern is just too dynamic to even provide a reliable guess. For detailed mountain weather information visit avalanche.ca/weather.

Avalanche Summary

Natural loose dry avalanches from size 1.5 to 2 were reported from alpine features facing North, Northeast, East and and Southeast over the weekend.

Snowpack Summary

Our relatively young snowpack is already quite complicated.  Tuesday night's storm brought 5 to 10 cm that is likely being formed into small storm slabs.  Previous to this, northerly winds associated with last weeks outbreak of Arctic air stripped many south facing features down to rock near ridge crest. As a result, wind slabs that have now grown old and tired were reported on north facing features at and above treeline. The cold air and associated inversion created surface facets and the well reported trophy sized surface hoar that averages 20mm in size and can be found from creek bottom up to around 1800m. Sun and above freezing alpine temperatures were also part of the last week of wonky November weather, so you'll find a suncrust at and above treeline just under the new storm snow on solar aspects. The three different November surface hoar interfaces that we were previously concerned about seem to be a thing of the past. It's thought that there is also a crust/facet interface on or just above the ground on high elevation north facing features, but this interface is likely very isolated and is probably inactive at this time.

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