Bulletin d’avalanche

Sea To Sky

Feb 4 – 5, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Mon
Tue
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

7am update: Storm snow and extreme southwest winds are building reactive storm slabs in lees and creating dangerous avalanche conditions. Avoid freshly wind-loaded features.

Problèmes avalancheux

  • Storm Slabs

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

    Storm snow is covering a variety of surfaces including stiff wind slabs and a faceting crust of varying thicknesses. Investigate how new snow is bonding to the surfaces below it.

    Strong southwesterly winds are transporting storm snow into deep pockets in lees. Be especially cautious as you transition into wind-affected terrain. Watch for an increase in slab properties in wind-blown areas as snow continues to accumulate throughout the day.

Confidence

Moderate

Avalanche Summary

On Thursday, several small wind slab avalanches were skier accidentally triggered, skier remotely triggered and naturally triggered up to size 1. All avalanches were reported on north and east aspects at 2000 m.

If you head to the backcountry please post your reports and photos to the Mountain Information Network, the information is very helpful to forecasters.

Snowpack Summary

+20 cm of storm snow overlies variable surfaces including old wind slabs and a crust of varying thicknesses. Extreme southwest winds are transporting storm snow and building deep pockets in lees.

A crust from mid-January can be found down 40 to 70 cm deep. A number of weak layers exist within the middle and lower snowpack, but the thick crusts sitting above them make triggering avalanches on these layers unlikely. The areas of concern in terms of triggering a deeper layer are shallow rocky areas.

Weather Summary

Friday night

Mainly cloudy with flurries, 20- 30 cm accumulation. Southwesterly ridgetop winds 40 to 60 km/h. Treeline temperatures -2 ˚C. Freezing levels fall to 1100 m from 1500 m.

Saturday

Cloudy skies and scattered flurries, 5-15 cm accumulation. 20 to 40 km/h southerly ridgetop wind, treeline temperatures warm to -1 ˚C. Freezing levels 1400 m.

Sunday

Cloudy skies and scattered flurries, 5-10 cm accumulation. Southwesterly ridgetop winds 20 km/h gusting to 40 km/h. Treeline temperatures warm to -1 ˚C. Freezing levels 1300 m.

Monday

Cloudy with isolated flurries, 10-15 cm accumulation. Southwesterly ridgetop winds 40 to 60 km/h. Treeline temperatures warm to -1 ˚C. Freezing levels 1300 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Dial back your terrain choices if you are seeing more than 30 cm of new snow.
  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Minimize exposure during periods of heavy loading from new snow and wind.

Régions couvertes