Bulletin d’avalanche

South Rockies

Mar 21 – 22, 2015Avalanche Canada
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Archivé · expiré 12 years ago

Danger d’avalanche

Mon
Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

It's still winter at and above treeline and the current avalanche problems dictate careful terrain selection.Check out the new video by the South Rockies Field Team in our blog section: www.avalanche.ca/blogs

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Ongoing strong winds are likely continuing to form fresh wind slabs in wind exposed terrain at and above treeline. Warming temperatures Sunday afternoon could increase the reactivity of said slabs.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Loose wet avalanches can really pack a punch at this time, especially below treeline as the temperature rises above freezing.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    3–6
    A crust/facet layer down 90 to 150cm still has the potential to produce very large avalanches with a heavy trigger like cornice failure or a surface avalanche in motion.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Monday

Weather Forecast

Sunday: Clear skies in the morning, cloud cover increasing throughout the day. Strong winds out of the SW at treeline, NW at ridgetop, backing off as the day goes on. Freezing level starting at 800m, rising to 2300m.Monday: Overcast skies. Light variable winds at all elevations. 5 to 15cm of snow possible. Freezing level starting at 600m, rising to 1500m in the afternoon. Tuesday: Scattered cloud. No significant precipitation expected. Light variable winds at all elevations. Freezing level starting at 600m, rising to 1500m in the afternoon.

Avalanche Summary

No new avalanche activity to report from Friday. A widespread natural avalanche cycle to size 2.5 occurred on Monday during the storm. These were primarily storm slab avalanches but several stepped down to deeper persistent weak layers or to the ground in steep unskiable terrain. At lower elevations, loose wet avalanches up to size 2.5 were reported as well as isolated wet slabs. Natural avalanches quickly tapered off during the storm but touchy conditions existed through the week. Winds increased on Thursday and wind slab formation has been ongoing since.

Snowpack Summary

A moist or wet snow surface is expected on all aspects to around treeline and on sun-exposed slopes into the alpine. Dry snow can likely still be found on sheltered high elevation slopes. Ongoing strong SW winds are redistributing the surface snow in exposed high elevation terrain.  A weak rain crust from last weekend is down 30-50cm and has a good bond with snow above. There are a couple older persistent weak layers in the midpack that are still intact and have the potential to wake-up with substantial warming or heavy loading. Cornices may become fragile with afternoon warming.

Régions couvertes