Bulletin d’avalanche

South Coast Inland

Mar 29 – 30, 2022Avalanche Canada
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Archivé · expiré 5 years ago

Danger d’avalanche

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

A skiff of new snow may not be enough to float us over the firm surface underneath. Prepare for challenging travel conditions, and watch for loose wet and windslab avalanche hazard on isolated terrain. 

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Moderate southwest wind and the possibility of new snow may form small, reactive windslabs over firm surfaces. 

    • Watch for signs of instability like shooting cracks and recent avalanches.
    • Windslabs can be most reactive when they are fresh, so tune in to loading patterns when you see blowing snow. 
    • Use small test slopes to see how windslabs are bonding to the old surface.

  • Loose Wet

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

    Freezing levels are dropping, but mild daytime warming and spots of intense spring sun could make loose wet avalanches possible. 

    The size of these avalanches will be mostly influenced by how deep the loose snow is. 

    • If there is a solid, supportive crust on the surface, avalanches will be unlikely. 
    • If the temperature is above zero, the sun is on a slope, and there is very little wind to keep the surface cool, avalanches will become more likely.

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Weather Forecast

TUESDAY NIGHT: Mostly cloudy. Light snow/rain expected, but up to 8 cm east of Pemberton. Light to moderate southwest ridgetop wind, with periods of strong in the high alpine. Freezing level falls to around 1300 m.

WEDNESDAY: Mostly cloudy. Light snow/rain expected, but up to 5 cm east of Hope. Light to moderate southwest ridgetop wind. Freezing level around 1300 m. 

THURSDAY: A mix of sun and cloud. Light snow/rain expected. Light southwest ridgetop wind. Freezing level falling to around 750 m overnight and rising to 1500 m through the day.

FRIDAY: Mostly cloudy. Light snow/rain expected. Light southwest ridgetop wind with periods of strong in the high alpine. Freezing level falling to around 750 m overnight and rising to 1500 m through the day.

Avalanche Summary

On Tuesday, a few small wet loose avalanches were reported in the south end of the region.  

Saturday, Sunday and Monday, small loose wet avalanches were naturally triggered by warm temperatures and sunshine.

Snowpack Summary

In localized areas on the Duffy and around Hope, up to 10 cm of new snow falling with moderate southwest wind may form small, reactive windslabs on old, firm surfaces. With freezing levels falling to 1300m, a frozen crust is expected on all aspects into the alpine. In the northern end of the region, on the few peaks above 2500 m, cold, winter snow may be found in shaded alpine terrain, with a sun crust on south facing slopes.

The rest of the upper snowpack consists of a number of crust/facet/surface hoar interfaces buried in March that seem to have bonded during the recent warm weather. 

The mid and lower snowpack are generally strong and well bonded. 

Terrain and Travel

  • Be alert to conditions that change with aspect and elevation.
  • When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

Régions couvertes