Bulletin d’avalanche

Kootenay Boundary

Jan 26 – 27, 2021Avalanche Canada
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Archivé · expiré 6 years ago

Danger d’avalanche

Thu
Fri
Alpin
1 · Faible
Limite forestière
1 · Faible
Sous la limite
1 · Faible

Points saillants

Low hazard doesn't mean no hazard! Watch for isolated pockets of wind slab at upper elevations and remember that small avalanches can have big consequences in certain terrain features, like above cliffs or terrain traps.

Problèmes avalancheux

  • Wind Slabs

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

    Wind slabs trend less reactive as they facet and lose cohesion in cold temperatures. Isolated pockets may remain triggerable where they sit over a crust or surface hoar.

  • Persistent Slabs

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

    Continued caution is warranted around steep, shaded slopes around treeline where pockets of buried surface hoar may still be preserved.

Snowpack Summary

One or more crusts may exist in the upper snowpack depending on elevation and area within the region. The uppermost crust extends up to around 2000 m (i.e. ridgetop in areas such as Rossland). In higher terrain, 10-15 cm of wind affected snow may sit over a crust and/or large surface hoar crystals.

A layer of surface hoar found 20-50 cm below the surface in isolated areas in the north and east of the region appears to be gaining strength. Recent test results suggest that it may be possible to trigger this layer in isolated areas, but it has not produced any avalanches in over a week.

A couple of crusts surrounded by weak faceted grains are buried deep within the snowpack. The upper layer is 80 to 130 cm deep and the lower is near the ground. 

Terrain and Travel

  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Confidence

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

Weather Forecast

MONDAY NIGHT - Cloudy with clear periods and a few flurries / light south wind / alpine low temperature near -10

TUESDAY - Mainly cloudy with a few flurries / light to moderate south wind / alpine high temperature near -8 

WEDNESDAY - Mainly cloudy with a few flurries, 5 cm / moderate to strong south wind / alpine high temperature near -7 

THURSDAY - Flurries, 5-10 cm / moderate to strong southwest wind / alpine high temperature near -5

Avalanche Summary

One size 1 human triggered wind slab avalanche was reported on a northeast aspect at 2000 m in the Five Mile Provincial Park area on Saturday. This is a good reminder of the hazards that still need to be managed during times of relatively low danger. Otherwise, there have been no new reports of avalanches in the last couple of days. 

Régions couvertes