Bulletin d’avalanche

Kootenay Boundary

Feb 23 – 24, 2016Avalanche Canada
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Archivé · expiré 11 years ago

Danger d’avalanche

Thu
Fri
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré

Points saillants

Cautious terrain selection is critical these days. Pay attention to daytime heating on solar aspects and avoid cornice features.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Use caution in terrain that was affected by wind during the last storm
  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–4
    Cornices may become weak with daytime heating.  Give them a wide berth.
  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–5
    The storm slab should be bonding on north aspects, but may become reactive on solar facing slopes.

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

A ridge of high pressure has moved in over province. We should see mostly sunny skies with a few clouds and the possibility of morning valley fog in some areas. Freezing levels are forecast to rise to 1500 metres during the day, but should drop to valley bottoms overnight. On Friday, freezing level may go to 3000 metres.

Avalanche Summary

Reports from yesterday tell us that wind slab avalanche activity is still not over.  A widespread cycle of natural activity in the Bonnington range up to size 2.5 was also reported, and seems to have been the storm snow from the last wind and snow event. The February crust interface mentioned in the Snowpack Discussion section appears to be still active in some parts of the region, and is still something to be wary of.  Warm temperatures and increased radiation on solar aspects makes for a good recipe for large avalanches.

Snowpack Summary

A considerable amount of snow fell during the past week, with the eastern part of the region receiving the most out of the storms. Moderate to strong south west winds have redistributed the surface snow into touchy wind slabs.  A melt-freeze crust that formed during the 2nd week of February has been reported at various levels from 50 to 120cm throughout the region. This crust is widespread and may co-exist with surface hoar or weak facets, especially at treeline and below on north aspects. This reactive interface is a critical layer to watch in the region, and has been the active layer for some very large avalanches recently. Buried surface hoar layers exist in the drier areas on the west side of the region near Rossland and are worth keeping in mind. Surface hoar growing up to 6mm has been reported in the past 2 days throughout the region. Sun crust may exist on solar aspects at the surface and has also been reported in the region 20cm below the surface.  Daytime heating will help settle the snowpack but could also make for touchy conditions on south facing slopes in the afternoon. Cornices can grow weak with daytime heating.

Régions couvertes