Bollettino valanghe

South Columbia

Apr 10 – 11, 2015Avalanche Canada
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Archiviato · scaduto 11 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole

In sintesi

If alpine storm snow totals are less than 10cm, the alpine danger rating will likely be Moderate.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–3
    A relatively small amount of snow Friday night and Saturday accompanied by strong SW winds will likely result in the development of thin fresh wind slabs. These slabs are expected to be most sensitive immediately lee of ridge-crest.
  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–5
    Increased winds Friday night and Saturday will add to the already large cornices that loom over many features, potentially increasing the likelihood of failure. Cornice failure has the potential to release slabs on slopes below.

Confidence

Fair - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

FRIDAY NIGHT: 2 to 5mm of precipitation is possible, less than 10cm of total snow expected. Extreme SW winds.SATURDAY: Freezing level hovering around 1500m. 2 to 6mm precipitation resulting in 2 to 10cm of snow. Moderate SW winds at treeline, moderate to strong SW/W winds at ridge-top.SUNDAY: Freezing level starting at 1000m, rising to 1500m. Light W/SW winds treeline, Moderate W winds at ridge-top. Overcast. No significant precipitation expected.MONDAY: Freezing level hovering around 1500m. Light variable winds at treeline. Moderate SW winds at ridge-top. Overcast. No significant precipitation expected.

Avalanche Summary

In two separate incidents Thursday cornice fall triggered deep persistent slabs when it impacted slopes below. Both incidents were on north facing alpine features. Loose wet avalanches to size 2 were also observed from south through west facing terrain.

Snowpack Summary

The current surface consists of surface facets and surface hoar. Below this is the 10 to 45cm of snow that fell last weekend. This snow remains dry on high elevation polar aspects but has turned moist on east and west facing aspects and south facing features are moving into the spring corn cycle. Just below this snow you'll 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. Although they appear to have gone dormant for the time being, we will continue to monitor them closely. 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 an avalanche failing at either of these interfaces is unlikely, it may still be possible on steep unsupported alpine features.

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