Bulletin d’avalanche

South Columbia

Apr 8 – 9, 2015Avalanche Canada
Voir sur la carte
Archivé · expiré 11 years ago

Danger d’avalanche

Fri
Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
Ouvrir la carte complète

Points saillants

Direct sun & warmth are currently the primary drivers of hazard and the weather forecast indicates that Thursday will be quite warm. Minimize your exposure to large slopes if the snowpack is becoming moist or wet.

Problèmes avalancheux

  • Cornices

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–5
    Thursday looks to be the warmest day in recent memory. As the mercury rises cornices become more prone to failure. While falling cornice is in itself problematic, this mechanism could drive persistent slab release on slopes below.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–7
    It's tough to say which features harbor a trigger-able weakness and which don't with any amount of certainty, but cornice fall driven by warm temperatures is the most likely trigger.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–2
    Loose avalanche activity should peak Thursday as the freezing level creeps well into the alpine. Loose wet avalanches are possible on all aspects. While slow moving, these avalanches can be very powerful and you do not want to be caught by one.

Confidence

Fair

Weather Forecast

THURSDAY: Freezing level starting at 1200m, rising to 2200m. Light W/NW winds at all elevations. No significant precipitation expected. Clear skies.FRIDAY: Freezing level holding at 1800m. Moderate S/SW winds at treeline, strong S/SW winds at ridge-top. No significant precipitation expected. Cloud cover rapidly building to overcast by lunch.SATURDAY: Freezing level hovering around 1500m. 2 to 8mm precipitation, 2 to 15cm of snow possible. Moderate SW winds at treeline, strong SW winds at ridge-top.

Avalanche Summary

Observations from Sunday, Monday and Tuesday were limited to power sluffing from steep high elevation terrain and small loose wet activity.

Snowpack Summary

Surface faceting is beginning to work on the 15 to 45 cm generated by convective snow fall over the weekend. This snow remains dry on high elevation north facing features, but is moist almost everywhere else. Just below this snow you'll find tired old wind slabs at upper elevations and the supportive late-March crust that is thought to exist up to around 2100m. Moist snow underneath the late-March crust is ubiquitous in most of the region.Two significant persistent weak layers composed of crust and facets exist in the snowpack. Mid-March is down 40 to 80cm below the surface and Mid-February is down 80 to 140cm. Observations indicate that there is significant faceting occurring between the two crusts. While avalanche activity on these weak layers has tapered off snowpack tests indicate that these layers may still be sensitive to triggering.

Régions couvertes