Avalanche forecast

Purcells

Jan 31 – Feb 1, 2013Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Moderate to strong winds are expected to continue to develop fresh new wind slabs in the alpine and at treeline in the lee of terrain features. Expect wind slabs to become stiffer with continued wind transport.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–3
    The recent storm snow continues to settle into a cohesive slab above weak layers and variable old surfaces. This slab may become more reactive during the forecast warm temperatures and solar radiation.

Confidence

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

Weather Forecast

Overnight and Friday: 2-3 cms expected tonight combined with strong Northwest winds and alpine temperatures about -8.0. Snow ending by morning, becoming high overcast with freezing level rising to about 1300 metres and light Northwest winds.Saturday: Mostly sunny with light West winds. Above freezing temperatures are expected in the alpine up to about 2300 metres.Sunday: The next Pacific disturbance is expected to move into the interior from the coast. Temperatures should drop below freezing at all elevations before the system arrives.

Avalanche Summary

Natural and skier controlled avalanches were reported  up to size 2.0 on North thru East aspects in the alpine and at treeline. Loose snow sluffing in steep terrain continues to be reported up to size 1.0.

Snowpack Summary

Westerly winds and warm temperatures overnight have continued to develop wind slabs in the alpine and at treeline. Wind slab was reported to be stiffening from fist to four finger hardness. The recent storm slab has been settling and becoming more cohesive. Pockets of slab that were mostly between 30-50 cms deep above the January 23rd weak layer have started to release naturally or when light additional loads have been added (like ski-cutting). As we head into a warming period expect the recent storm slab to become more reactive. The forecast warm temperatures at higher elevations on Saturday may help initiate releases on the January 23rd layer. The deeper weak layer from January 4th is reported to be gaining strength, and I don't expect that we will see releases on this layer from one day of solar radiation and warm temperatures. That being said, if cornices start to fall off from the heating on Saturday, that might be enough of a load to trigger the deeper January 4th layer.

Regions covered