Bulletin d’avalanche

South Rockies

Mar 10, 2017Avalanche Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

Fri
Sat
Alpin
4 · Fort
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Points saillants

Storm loading will promote touchy conditions on Friday. Expect the avalanche danger to increase throughout the day.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–3
    On Friday, new snow and wind will form touchy storm slabs which are expected to be most reactive in wind-exposed terrain. Watch for conditions that intensify throughout the day.

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    2–4
    Recent observations in the Elkford area suggest deep persistent slabs should be on your radar. Likely triggers for these destructive avalanches include storm loading, cornice falls or solar radiation, all of which are expected over the next few days.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Saturday

Weather Forecast

Thursday night: 6-12cm of new snow / Moderate southwest winds / Alpine temperature of -8Friday: 8-15cm of new snow / Strong to extreme southwest winds / Alpine temperatures of -3 (freezing levels at 1500m)Saturday: Clear skies in the morning with increased cloud in the afternoon / Light southwest winds / Alpine temperature of -3Sunday: Light flurries / Light southwest winds / Alpine temperature of -4

Avalanche Summary

On Thursday, our Avalanche Canada Field Team observed evidence of a few naturally triggered size 2 slab avalanches in the Crossing Creek area. While one of the avalanches appeared to have failed within the recent storm snow, one avalanche was about 1m deep and is thought to have been triggered on the December facet layer near the base of the snowpack. This event highlights the isolated yet potentially destructive nature of the deep persistent avalanche problem which should become more prevalent as we head into spring.Looking forward, natural wind slab and storm slab activity is expected to ramp-up again in response to new snow and wind on Thursday night and Friday.

Snowpack Summary

By Friday morning expect 6-12cm of new snow with lots more falling throughout the day. Strong southwest winds are expected to shift these accumulations into much deeper deposits in exposed lee terrain. Over the past week we've had daily snowfalls of 5-15cm bringing the storm total to 50-90 cm. In some areas, the resulting slab may have a poor bond to the old snow interface which consists of stiff wind slabs, crusts, and facets.The mid-pack in this region is generally strong, but the bottom third of the snowpack is composed of weak facets (sugary snow crystals). Approximately 100-120 cm of settled snow sits above this weak layer of sugary, rotten facets that developed in December. This remains a concern and should be on your radar, especially with the recent loading from snow and wind.

Régions couvertes