Avalanche forecast

Northwest Inland

Jan 17 – 18, 2013Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–4
    Strong westerly winds have created windslabs on lee terrain. With forecast snowfall and higher than normal wind values, watch for continued loading lower on the slope and in other unsuspecting locations.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Forecast snowfall will add additional load to buried weak layers. Watch for triggering in sheltered, unsupported terrain.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    A deeply buried facet/crust weakness exists near the base of the snowpack. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Overnight Thursday and Friday: Moderate snowfall becoming light on Friday / Strong to extreme southwest winds becoming moderate and northwesterly / Alpine temperatures at about -4.0Saturday: Light snowfall / Moderate west winds /  Alpine temperatures at about -2.0Sunday: Mainly dry conditions / Light southwest winds / Alpine temperature of about -1.0

Avalanche Summary

Due to inclement weather, observations have been limited; however, on Monday a size 2 windslab avalanche was skier-triggered in a chute above Crater Lake. The crown was about 30m wide with a maximum height of 80cm. On Tuesday a snowmobiler triggered a size 1 windslab on a slope which was reported to be "normally very stable". Forecast weather suggests that there will be ongoing windslab activity.

Snowpack Summary

Rain below treeline has continued to maintain moist surfaces at lower elevations. Moderate amounts of new snow and strong winds at higher elevations have most likely formed hard windslabs in the lee of terrain breaks and ridges.A surface hoar layer that was buried at the end of December is now down 60-80 cm, and was reactive in some areas with recent warming. An otherwise strong mid-pack overlies a weak base layer of facets/depth hoar and the remnants of a crust.

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