Bulletin d’avalanche

Kootenay Boundary

Feb 20 – 21, 2020Avalanche Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

Sat
Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

As you travel, use added caution on steep slopes in open trees, as the snow may rest on surface hoar. This layer may be most problematic around Kootenay Pass. At higher elevations, you may also find slabs in wind-loaded features.

Problèmes avalancheux

  • Storm Slabs

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

    A 20 to 30 cm slab has been reactive to riders in the past few days. The slab has been touchiest in open trees, where it rests on a layer of weak and feathery surface hoar. Near ridge lines, the slab is touchiest in lee terrain features due to recent wind transportation.

Confidence

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

Weather Forecast

WEDNESDAY NIGHT: Clear skies, light southwest wind, alpine temperature -6 C, freezing level below valley bottom.

THURSDAY: Clear skies, light to moderate southwest wind, alpine temperature -5 C, freezing level 1200 m.

FRIDAY: Clear skies, light to moderate southwest wind, alpine temperature -5 C, freezing level 1000 m.

SATURDAY: Mix of sun and cloud with isolated flurries, accumulation 1 to 3 cm, light to moderate west wind, alpine temperature -6 C, freezing level 1000 m.

Avalanche Summary

A few more slab avalanches were reported in the region on Tuesday. They mostly happened around Kootenay Pass and released on the surface hoar layer described in the Snowpack Summary. They have been releasing in sheltered terrain in open trees at and just below treeline. There are great examples of these avalanches on the MIN, summarized here.

Snowpack Summary

A 20 to 30 cm thick slab has been reactive to human traffic in the past few days. The slab may overly a weak layer of feathery surface hoar crystals in open trees. In the alpine near ridges, the slab has been most reactive on north to east to south aspects due to wind transportation. On south aspects, sunny skies have melted the surface snow, which will be wet during the daytime heat and freeze into a melt-freeze crust during the night.

A few other crusts exist in the top 100 cm of the snowpack; reports suggest that the overlying snow is bonding well to them.

Terrain and Travel

  • Approach steep open slopes at and below treeline cautiously, buried surface hoar may exist.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Minimize exposure to steep, sun exposed slopes, especially when the solar radiation is strong.

Régions couvertes