Bulletin d’avalanche

Northwest Coastal

Feb 9 – 10, 2015Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Wed
Thu
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

It's easy to feel euphoric when the snow is deep, it's sunny, and you're out with your buds. Make conservative decisions Tuesday and watch for signs of the approaching storm.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    4–8
    Limited observations mean there's a ton of uncertainty concerning the deeper problem layers in the snowpack. I would manage this by assuming that every slope above treeline has the potential to produce a very large and destructive avalanche.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–6
    Natural avalanches have ceased and this is when it gets tricky.  You may be gaining a bit of confidence, but this is when you're most likely to get involved in a wreck.  Give yourself a healthy margin for error if you're stepping out Tuesday.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Wednesday

Weather Forecast

After a clear and cold Monday night clouds should build through the day Tuesday. No precip is expected and winds should be light for most of the day Tuesday. By the time dawn breaks Wednesday it should be snowing and winds will likely be strong to extreme at all elevations. The freezing level is expected to rise to 1500m by Wednesday afternoon while extreme SW winds are raging at ridgetop. Look for 5 to 20cm Wednesday and another 5 to 20cm Wednesday night. The storm should change character Wednesday night as the freezing level climbs to around 2000m. There's an additional 5 to 10mm of water in the forecast for Thursday, this will likely fall as rain below 2300m. The freezing level is expected to remain around 2000m through Friday with small amounts of precipitation each day through the end of the weekend.

Avalanche Summary

No significant activity to report from Sunday. Scanning the facebook posts it sounds like at least two folks were involved in avalanches Saturday. Control work Saturday produced slab and loose dry avalanches to size 2.5 from virtually all aspects and elevations. It sounds like a lot of these were running on mid storm instabilities.

Snowpack Summary

The NW Coast is THE place to be in the province right now. Arctic air has kept things cool and the storm produced 50 to 100cm accompanied by screaming winds out of the E through SE. Initial observations are limited, but there are reports of 75 cm of wind affected snow at and above treeline. The late-January crust is thought to be down 50 to 150cm in the south of the region and about half this depth in the north. This crust may have surface hoar on it. The mid-January rain crust and/or surface hoar layer is down over 150cm in the south and has generally become inactive though it may still be a concern in thinner snowpack areas. The November crust/facet combo near the bottom of the snowpack is thought to be generally well bonded but may still be reactive in the far north of the region.

Régions couvertes