Avalanche forecast

Northwest Inland

Apr 9 – 10, 2015Avalanche Canada
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Avalanche danger

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

Observations and data are limited. Read the Northwest Coast bulletin for information on the touchy persistent slab problem, which may also be present and active in some northern parts of the inland region..

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Winds are forecast to be strong with the approaching frontal system. New snow will be blown into wind slabs in exposed lee terrain, possibly well below ridge crests. A small wind slab might trigger deeper instabilities.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    A buried layer of surface hoar layer on crust, now down around 50 cm, has been very reactive in the Ningunsaw Pass area and could be an issue in other parts of the region where we have received little info. This weak layer should not be trusted.

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

Thursday: Sunny with some clouds appearing late in the day, freezing level rising to around 11300m. Winds moderate to strong  from the S-SW. Friday: Light snow. The freezing level is near 1200 m and winds are strong from the south. Saturday: Cloudy with flurries. The freezing level is forecast to 1000 m and winds should be moderate from the SW.

Avalanche Summary

Loose wet avalanches to size 2 have been reported from steep sun-exposed slopes. Some of these triggered slabs up to size 2.5, possibly releasing on the March 25th surface crust/ surface hoar layer. Observers near the Ningunsaw Pass (northern part of the region) have reported significant activity on the March 25th interface. For the past few days there have been reports of natural, skier-triggered, and remotely triggered avalanches up to size 2.5.

Snowpack Summary

You may still find dry powder on higher north aspects, but any sun exposed slope will likely have been through a melt-freeze cycle. Recent winds have scoured windward slopes and loaded lee features. A crust with surface hoar buried on March 25th, down around 50 cm, has been identified as a potential problem in parts of the forecast region, but its sensitively and distribution are largely unknown. At the base of the snowpack, especially in areas of shallow snow, weak facets may be found. Cornices are now large and potentially fragile, and solar aspects are becoming active in the late afternoons. Spring is on the way !

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