Avalanche forecast

Northwest Coastal

Mar 13 – 14, 2013Avalanche Canada
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Avalanche danger

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

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–5
    Light snow and strong winds have created new wind slabs in exposed terrain. Wind slabs may be particularly reactive in areas where they overlie a weak layer of buried surface hoar and or crusts.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Thursday:  Continued moist precipitation.  10 -15mm/15-25cm expected over the south portion of the region, very little precip expected in the north.  Freezing Level: 200m.  Wind: Strong, South.Friday:  Occasional light showers/flurries. 10mm/10-20cm expected.  Freezing Level 300m.  Wind Strong, South.Saturday:  A weak pulse of moisture makes its way inland.  5mm water expected.  Freezing level tops out around 700m in the afternoon lowering to the surface by Saturday night.  Wind: Light, SW

Avalanche Summary

Reports from Tuesday include human and naturally triggered avalanches to size 2 on a variety of aspects.  In most of these avalanches the March 9th Surface Hoar/Facet/Crust combo is to blame.

Snowpack Summary

20 - 40cm of unconsolidated new snow is bonding poorly a variety of old surfaces which include: a crust at lower elevations and on solar aspects; old wind slabs in exposed areas, and fairly widespread large surface hoar. Moderate to locally extreme west/southwest winds have redistributed the new snow into soft and hard wind slabs in exposed terrain. This new snow is currently reactive to human triggers primarily where cohesive wind slabs have formed, but reactivity is expected to become more widespread as the overlying slab develops with continued loading. The mid snowpack layers are generally well settled and strong. Facets at the base of the snowpack may resurface as a concern now that spring warming is on the doorstep and full-depth releases are becoming more likely (primarily in the northern part of the region).

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