Avalanche forecast

Northwest Coastal

Mar 1 – 2, 2012Avalanche Canada
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Archived · expired 15 years ago

Avalanche danger

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

The snowpack is tricky to predict at the moment. Backcountry travel requires local knowledge, extensive experience and training. Please read the new Forecaster's Blog Post.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    New wind slab development will mainly exist on N-E slopes, and behind terrain features. Cracking, whumphing and/or hollow drum like sounds beneath you are all indicators of a unstable snowpack.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–6
    Forecast snow this weekend will add to the current slab over the persistent weak layers. This problem may exist in areas that overlie buried crusts, facets, old wind slabs, and/or sheltered areas with buried surface hoar.

Confidence

Fair - Intensity of incoming weather is uncertain on Friday

Weather Forecast

Friday: The approaching warm front brings moderate snow amounts near 10 cm. Ridgetop winds 30-50km/hr from the West. Treeline temperatures -8. Freezing levels could rise to 600 m. Saturday: Snow amounts up to 10-15 cm. Ridgetop winds moderate from the West. Treeline temperatures -8. Freezing levels valley bottom. Sunday: Significant change in weather. Precipitation heavy through the day, winds moderate from the SW. Freezing levels 300 m then dropping.

Avalanche Summary

Natural avalanches up to size 2.5 occurred Wednesday afternoon from mid-low elevation terrain. Sluffing is occurring from steep terrain. On Tuesday extensive avalanche control work with the use of explosives was completed. Results included 1 size 3, @ 1320 m , on an East aspect, and numerous size 1-2 on East aspects between 12-1300 m. The snowpack is very tricky at the moment. Backcountry travel requires local knowledge, extensive experience and training. The obvious clues that show snowpack instability may not be there. You need to dig deep, do your detective work and make good decisions

Snowpack Summary

Due to changing winds, wind slabs can be found on N-NE aspects and S-SW aspects in the alpine on exposed slopes at treeline. Currently, up to 60cm of snow sits over the mid February interface. This interface is variable, it consists of a strong melt freeze crust below 1000m, above 1000 m exists facets, surface hoar (in more sheltered areas), sun crust or wind press. The surface hoar is not widespread but is responsible for much of the larger avalanches that occurred earlier this week. This layer should be on your radar, as it's susceptible to rider triggers. With forecast wind, snow and rising freezing levels this layer may show its wrath again. It's a good time to play conservatively. Below this, the mid and lower snowpack is well settled and strong.

Regions covered