Bulletin d’avalanche

South Coast

Mar 16 – 17, 2023Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Sat
Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

Rising freezing levels and the sun can quickly destabilize the snowpack. Avoid sun-exposed slopes overhead hazards like cornices during the heat of the day.

Problèmes avalancheux

  • Wind Slabs

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

    Pockets of stiff wind slab may be reactive to human triggering on lee slopes at upper elevations.

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–2.5

    Large looming cornices exist along ridgelines. Cornices become weak with daytime warming and sun exposure. Give cornices a wide berth while traveling ridgelines and avoid slopes below them.

  • Loose Wet

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

    Strong solar radiation and rising freezing levels may weaken the surface snow creating wet loose avalanches on all aspects below 1300 m and steep solar slopes above.

Confidence

Moderate

Avalanche Summary

On Wednesday, pinwheeling was seen on solar aspects and small dry loose sluffing seen on shaded aspects.

On Tuesday, natural and skier-triggered dry loose avalanches up to size 1 were reported from the North Shore mountains.

On Monday, natural dry loose avalanches were reported from steep terrain features and explosive control initiated several storm slabs up to size 1. The storm slabs were 5 to 20 cm thick with very limited propagation and entrainment.

Natural and human-triggered avalanche activity will likely occur throughout the weekend with rising freezing levels and solar radiation.

Snowpack Summary

Daytime warming and solar radiation will promote moist snow surfaces, destabilizing the upper snowpack on all aspects up to 1300 m. Above this only steep solar slopes will be affected while northerly aspects should hold the dryer wintery snow longer. Southerly winds have also created wind slabs in exposed terrain at higher elevations.The recent 40 cm of storm snow is reportedly settling and bonding to the old buried crusts.

In general, the mid and lower snowpack is well-settled and bonded.

Weather Summary

Thursday Night

Clear with some cloudy periods. Treeline temperatures near +2. Wind southeast 15 km/hr and freezing level 1300 m.

Friday

A mix of sun. Treeline temperatures near +4. Winds southeast 20-30 km/hr. Freezing level 1600 m.

Saturday

A mix of sun and cloud. Treeline temperatures near +5. Wind southeast 15-20 km/hr. Freezing level 1700 m.

Sunday

Rain 10-20 mm. Winds 10-20 km/hr from the southeast. Treeline temperatures near +5 with freezing levels 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes