Bulletin d’avalanche

Northwest Inland

Apr 24 – 25, 2022Avalanche Canada
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Archivé · expiré 4 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré

Points saillants

Limited field observations have been made in the past week. 

Make observations as you travel and be on the lookout for signs that suggest unstable snow. Expect snow conditions to change quickly with elevation, aspect, and time of day. 

Problèmes avalancheux

  • Wind Slabs

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

    Recent snowfall and southerly winds may have formed pockets of wind slabs in lee areas in the alpine. 

    Use caution entering lee terrain features below ridges. The snow could slide easily where it rests on a hard melt-freeze crust or faceted snow. 

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    Cornices are large this time of year and may become weak with warm temperatures. Exposure to cornices should be minimized, especially during periods of warm temperatures or strong sun. Give them a wide berth when you are travelling on ridge lines and avoid overhead exposure to large cornices. 

  • Loose Wet

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

    Rain at lower elevations may cause the snowpack to become isothermal, producing wet loose activity on steep slopes at treeline and below. Glide slab activity has been noted on steep rock slabs and grassy slopes. Avoid travelling on or below slopes with large glide cracks.

    If the sun comes out on Monday, wet loose activity is likely on steep solar aspects at all elevations, especially where dry snow is seeing the sun for the first time.

Confidence

Low - Uncertainty is due to the limited number of field observations. Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

SUNDAY NIGHT: Cloudy with flurries, trace to 10 cm of new snow accumulation at higher elevations. Freezing level lowering to 1000 m. Light to moderate southwesterly winds.

MONDAY: Partially cloudy with light flurries, up to 5 cm of accumulation. Freezing level rising to 1400 m in the afternoon. Light to moderate southwesterly winds.

TUESDAY: A mix of sun and cloud with flurries, up to 5 cm of accumulation. Freezing level rising to 1500 m in the afternoon. Light southerly winds.

WEDNESDAY: Partially cloudy with isolated flurries. Freezing level rising to 1400 m in the afternoon. Light northwesterly winds. 

Avalanche Summary

Reports from the region have been very limited in the past week. Please let us know what you're seeing by filling out a MIN report!

Looking forward to Monday, we expect that reactive wind slabs may exist in lee terrain features in the alpine. Wet avalanche activity is possible on steep solar aspects and at low elevations with the potential for periods of strong solar radiation and rain.

Snowpack Summary

New snow and southerly winds are expected to create fresh deposits of wind slab in the alpine. This 5-10 cm of new snow overlies a heavily wind-affected surface in exposed terrain, the product of an intense wind event early last week. In sheltered areas, the upper snowpack is faceted from recent cold temperatures, and surface hoar may exist in isolated areas. A crust can be found on steep solar aspects and at low elevations, this crust may break down throughout the day with rain or strong solar radiation. The mid and lower snowpack is well bonded with no concerning weak layers. 

Terrain and Travel

  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • The more the snow feels like a slurpy, the more likely loose wet avalanches will become.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Régions couvertes