Bulletin d’avalanche

South Rockies

Dec 29 – 30, 2013Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Tue
Wed
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–3
    Strong SW winds continue to form snow into fresh sensitive wind slabs. Strong winds may have an effect on open slopes at treeline. Take care to avoid snow that feels stiff under your machine or skis and watch for signs of wind loading.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–5
    It's getting a little tricky out there.  Wind slabs avalanches have the potential to step down and trigger an avalanche on the buried surface hoar.  Plan an escape route when sizing up your lines and regroup in safe zones.

Confidence

Poor - Wind effect is extremely variable

Weather Forecast

Synopsis: NW flow continues to dominate the pattern. A few cms may make it into the region, but no significant accumulations are expected. The big player over the next few days will be the wind. 2000m wind forecasts are provided below, 3000m winds are roughly 1.5x greater.Monday: Freezing Level: Valley Bottom; Precip: Nil Wind: Mod NW/WTuesday: Freezing Level: Valley Bottom; Precip: 1/2mm 2/5cm Wind: Mod W switching to Strong NW near sundown.Wednesday: Freezing Level: Valley Bottom; Precip: Nil; Wind: Initially Mod NW switching to Light SW by Wednesday evening.

Avalanche Summary

On Christmas Eve a backcountry skier triggered a size 2 slab avalanche on an alpine slope in the Harvey Pass area. The slab was reportedly 70cm deep and 150m wide and was thought to have slid on the late-November crust/facet interface. There were no reported injuries with the avalanche.No other avalanches have been reported.

Snowpack Summary

There appears to be a lot of snowpack variability across the region. Snowpack depths at treeline seem to vary from 60 - 130 cm with high variability in wind-exposed areas. Winds have been strong out of the SW on Sunday at all wind stations.  With 10 - 15 cm available for transport I expect wind slabs to be touchy on Monday.  In the mid pack is the late-November/early-December interface which is made up of surface hoar, a crust, and/or facets. This layer is typically down 30-70cm and has reached the tipping point for rider triggering in a few areas including the Harvey Pass area.  Check out this video of a recent snowpack test on this layer.  We're probably getting close to this layers tipping point in wind loaded terrain at treeline in much of the region. 

Régions couvertes