Bulletin d’avalanche

South Coast

Mar 24 – 25, 2021Avalanche Canada
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Archivé · expiré 6 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Recently formed slabs are likely bonding but could still be triggered by riders, particularly in steep terrain. Use caution around cornices and on sun-exposed slopes during the heat of the day.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–3

    Cornices are large and looming along many ridgelines, and have likely grown with the recent snow and wind.

  • Storm Slabs

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

    Storm and wind slabs formed on Tuesday may continue to be reactive to riders. The reactivity of slabs should be assessed before approaching steep open terrain, especially where exposed to the wind. 

  • Loose Wet

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

    Wet loose avalanche activity is possible if sunny skies prevail. This will be the first time all the recent snow has seen a good warm-up so avoid sun-exposed slopes should you find wet, sticky snow.

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

WEDNESDAY NIGHT: Clearing, 20 km/h north wind, freezing level 1000 m with treeline temperatures around -1 C.

THURSDAY: Sunny skies with periodic clouds, light northeast wind, freezing level climbing to 1500 m with treeline temperatures near 1 C.

FRIDAY: Mostly cloudy, light northwest wind, freezing level around 1000 m with treeline temperatures -1 C. 

SATURDAY: Cloudy, moderate southwest wind, freezing level rising to 1500 m with treeline temperature near 1 C.

Avalanche Summary

On Wednesday, riders triggered loose dry avalanches, which switched to loose wet as the freezing level rose over the day. The avalanches were reported as small (size 1). On Tuesday, this MIN describes recent slab avalanche activity near Mt Strachan. On Monday there were some reports of size 1.5-2 human triggered avalanches in the Seymour backcountry (30-60 cm thick). See the photos here and here. Additionally there were reports of several size 1.5 explosives triggered storm slab avalanches.

Looking forward, storm and wind slabs may remain triggerable at higher elevations and use caution on sun-exposed slopes if clear skies prevail.

Snowpack Summary

10 to 15 cm of snow accumulated on Tuesday night, forming new storm slabs and wind slabs in exposed terrain. This snow overlies 35 to 45 cm of snow from Sunday, which is likely now settled and bonded to the snowpack. The snow surface may moisten on Thursday during periods of sunny skies and with a freezing level rise to 1500 m. Along ridgelines, cornices are large and always have the potential of failing or being triggered from the weight of a human.

Terrain and Travel

  • The new snow may require another day to settle and stabilize.
  • Be careful as you transition into wind affected terrain.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes