Avalanche forecast

Northwest Inland

Feb 25 – 26, 2013Avalanche Canada
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Avalanche danger

Wed
Thu
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
    Pockets of dense wind slab are likely in exposed lee terrain and cross-loaded gully features. Triggering is possible on steep open slopes and convex rolls.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Cornices have grown large and weak in recent storms. They may fail with additional growth, daytime warming, or solar radiation.

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Synopsis: A frontal system will hit the coast early on Tuesday spreading moderate snow and increasing winds. This is followed closely by a second system late Wednesday.  Tuesday: Light to locally moderate snowfall – 5-10 cm. The freezing level is around 600 m and winds increase to very strong from the south-southeast. Wednesday: Unsettled with light snow during the day and heavier snow in the evening (5-10 cm). The freezing level is steady near 600-700 m and winds remain strong from the south-southwest. Thursday: Light to moderate snow. The freezing level climbs closer to 1000 m.

Avalanche Summary

There are a few reports of size 1-2 natural wind slabs from immediate lee and cross-loaded features. Slope testing also resulted in a few size 1 slabs in steep wind-loaded features.

Snowpack Summary

A new sun crust has formed on steeper solar aspects. In shady areas there is 40-60 cm of well settled storm snow. Strong southwest winds formed touchy wind slabs in exposed terrain in lee of ridges, in gullies, and behind terrain features. There are a variety of old interfaces now down 60 - 100cm which include facets, crusts and isolated pockets of surface hoar. Recent observations indicate that these weaknesses have bonded fairly well now, but I still suggest digging and testing the snowpack to confirm.A strong mid-pack currently overlies a weak base layer of facets/depth hoar. It is worth noting that the snowpack in general is quite shallow in northern and eastern parts of the region. Triggering the basal weakness may still be possible from thin spots, rocky outcrops or under the weight of larger triggers such as cornice fall.

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