Bulletin d’avalanche

Northwest Coastal

Dec 22 – 23, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Sat
Sun
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Friday into Saturday is a major weather transition period. Expect high precipitation amounts, warming temperatures and a rapidly rising avalanche danger.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Wind slabs exist in the alpine and open areas at treeline elevations due to reverse loading created by strong outflow winds. Winds slabs could overlie a weak layer of surface hoar, facets, and/or a crust. Any avalanche in the upper snowpack has the potential to scrub down to these deeper weak layers, making for larger-than-expected avalanches. This is especially relevant at treeline elevations, where surface hoar is more likely larger and better preserved.

Avalanche Summary

No new avalanches have been observed or reported in the past 24 hour period. Continue to support your backcountry community and please consider submitting a MIN report, Your information sharing is vital.

Confidence

Moderate

Snowpack Summary

Upper elevations surfaces have been exposed to sustained strong to extreme North wind. These surfaces are generally very hard and in places the snow has been stripped to the ground. Expect areas just below ridgetop on southerly aspects to accumulate snow as north winds are forecast to continue. In some parts of this forecast area, a crust exists on south aspects. As the temperatures have continued to remains very cold, faceted surface snow in protected lower elevation terrain is present. I would suggest the best riding and sliding opportunities exist in this elevation band.

A layer of large surface hoar crystals, buried in early December, is found down 20 to 50 cm. This layer has previously produced small but remotely-triggered avalanches. Continued reverse-loading is increasing the potential for deeper and bigger wind slabs.

The lower snowpack is well consolidated above the mid-November crust, found at treeline below 1200 m.

Weather Summary

A cold arctic air mass over the region will continue to bring to the forecast area. gusty outflow winds through the coastal inlets and extremely cold temperatures. Beginning late Friday, a series of weather systems are expected to deliver in excess of 70 cm of new snow with potentials for amounts greater than 100 cm. A rapid rise in temperature and freezing level is expected Saturday with models indicating a brief period of above freezing at 2500 meter elevations.

Wednesday night

Clear. No precipitation. North wind 40-60 km/h at ridge tops. Low of -25˚C.

Thursday

Mostly clear. No precipitation. North wind 15-20 km/h at ridge tops. High of -20˚C.

Friday

Snow 15-20 cm. Northeasterly wind, switching to Southeasterly wind that will build to 50 km/h at ridge tops. High of -12˚C..

Saturday

Snow 30-70 cm. Southeasterly wind 50 km/h at ridge tops. High of 0˚C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be carefull around freshly wind loaded features.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.
  • Seek out wind sheltered terrain below treeline where you can avoid wind slabs and find great riding.

Régions couvertes