Bulletin d’avalanche

Banff Yoho Kootenay

Mar 4 – 5, 2018Parks Canada
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Archivé · expiré 9 years ago

Danger d’avalanche

Mon
Tue
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

10-20cm of storm snow has made for excellent skiing! Our main concerns are small buried wind slabs and sluffing in steep terrain. We removed the persistent slab problem because of a lack of activity on this layer, but the structural weakness remains.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5
    Wind slabs covered by 10-20cm of loose snow exist in lee areas in the alpine. They have not been very easy to trigger, but do have potential to carry you into an undesirable location (cliffs/terrain traps) if they fail in steep terrain.

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5
    10-20 cm of storm snow has fallen with little wind. In many places this sits over loose facets from the last cold snap and with any increase in wind, or skier triggering, we will see small sluffs traveling a long ways in steep terrain.

Weather Forecast

A few more cm's of new snow are forecast for Saturday night and Sunday with continued light winds switching from E to SW overnight. Temperatures are forecast to remain cool (-5 to -15°C)  depending on elevation with a slight increase Sunday afternoon.

Snowpack Summary

10-20 cm of storm snow with little wind effect sits over buried wind slabs in open areas at higher elevations, and over loose facets at lower elevations. Below this a firm mid-pack covers the Jan surface hoar layers that are rounding and inactive in tests. The deeper facet layers down 80-150 cm remain weak but are presently difficult to propagate.

Avalanche Summary

Small loose snow avalanches/sluffing has been reported in some steep treeline areas with the storm snow failing on the facets below and running a fair distance. A couple small buried wind slab failures have also been reported recently in steep terrain. The persistent weak layers have been inactive for two weeks and have been removed as a problem.

Confidence

Wind speed and direction is uncertain on Monday

Régions couvertes