Avalanche forecast

Sea To Sky

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
2 · Moderate
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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–5
    Wind slabs will continue to form through the forecast period from new snow and moderate-strong SW winds. Cracking, whumphing and/or hollow drum like sounds beneath you are all indicators.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    With forecast snow through the weekend, storm slabs will continue to form. This adds to the current storm slab instabilities; especially in areas where they overlie preserved stellars, crusts, facets, and/or sheltered areas with buried surface hoar.

Confidence

Fair - Intensity of incoming weather is uncertain on Sunday

Weather Forecast

Friday: An approaching warm front from the NW will bring light- moderate snow amounts up to 10 cm. Ridgetop winds moderate from the SW. Treeline temperature near -5. Freezing levels could rise to 800m. Saturday: Snow amounts up to 10 cm. Ridgetop winds moderate-strong from the SW. Treeline temperatures near -2. Freezing levels rising to 12-1500 m. Sunday: Cloudy, snow amounts 5-10 cm. Ridgetop winds moderate from the SW. Freezing levels should drop to 1000 m.

Avalanche Summary

Small size 1-1.5 natural avalanche activity occurred early Wednesday with arrival of new snow. Several reports of rider triggered size 1-2 avalanches occurred on Wednesday. They occurred on most aspects from 1500-2000m, the preserved stellar layer down 20-40 cm seemed to be the culprit. With forecast snow and wind, avalanche conditions will remain touchy, and susceptible to rider triggers through the forecast period.

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. A thin suncrust has formed on Southerly aspects; I suspect this may become more distinct after Thursday. Reports of a preserved stellar layer exist down 20-40 cm. This layer has been reactive to rider triggers and should remain on your radar. Up to 60cm sits over a variety of old surfaces. These include melt-freeze crusts at lower elevations, old sun crusts on Southerly aspects into alpine elevations and spotty areas of surface hoar in sheltered treeline areas. Where they exist, they may act as sliding layers. The mid and lower snowpack is well bonded and strong.

Regions covered