Bulletin d’avalanche

Long Range Mountains

Mar 18 – 21, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
Sans niveau
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Points saillants

Avalanche danger will increase on Sunday and Monday with the incoming storm, especially on wind-loaded slopes.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely - Very Likely
    Taille
    1–2.5

    The size and likelihood of avalanches on wind-loaded slopes will increase as the storm progresses:

    • Sunday: Small avalanches will be possible for human-triggering below ridgelines and the on the sides of steep gullies.

    • Monday: Large natural avalanches can be expected and human triggering will be very likely on wind-loaded slopes.

    • Tuesday: Natural activity will taper off, but large human triggered avalanches will still be likely.

Confidence

Moderate

Avalanche Summary

A few old cornice and wind slab avalanches were observed by our field team on Friday, with photos of conditions before on storm in their MIN report. Looking forward, the primary concern is avalanches forming as slopes are loaded by new snow and wind.

Snowpack Summary

Snow conditions will change dramatically over the next few days. New snow will start to accumulate on Sunday with a total of 20 to 50 cm possible by the time the storm eases on Tuesday. Strong westerly winds throughout the storm will cause a variable distribution of the new snow, with much deeper deposits on leeward terrain features.

The storm snow will sit over a mix of hard layers including a potential freezing rain crust, a temperature crust, or wind-hardened layers. Smooth crusts will be the most concerning, as they could become a sliding layer for the new snow.

The lower snowpack is dense and bonded, with a few crust layers found throughout.

Weather Summary

Saturday night

Cloudy with light snowfall, up to 5 cm in the south and a trace in the north, moderate southeast wind with gusts to 50 km/h, mountain temperatures around 0 °C.

Sunday

Mixed precipitation with freezing rain possible in the morning turning to snow in the afternoon, 5 to 15 cm of snow possible depending when and where cooling begins, extreme southwest wind with guts to 90 km/h, mountain temperatures around 0 °C in the morning then cooling to -3 °C.

Monday

Heavy snowfall throughout the night and morning with accumulations of 15 to 25 cm in the south of the region and 25 to 40 cm in the north, extreme west wind with gusts to 90 km/h, mountain temperatures around -5 °C.

Tuesday

Cloudy with scattered flurries bringing up to 5 cm of snow, strong northwest wind with gusts to 60 km/h, mountain temperatures around -7 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Minimize exposure during periods of heavy loading from new snow and wind.
  • Avoid freshly wind loaded terrain features.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes