Boletín de aludes

Purcells

Dec 28, 2016Avalanche Canada
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Archivado · caducó 10 years ago

Peligro de aludes

Wed
Thu
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil

Lo esencial

The local avalanche danger may be higher in the north of the region where buried weak layers have recently produced large, destructive avalanches.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2
    Strong winds forecast for Wednesday may redistribute loose surface snow into fresh wind slabs. Watch for triggering in exposed higher elevation terrain.
  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible - Likely
    Tamaño
    2–3
    Recent avalanches show that persistent slabs are a concern in the north of the region. The mid-December weak layer has recently been reactive to human triggering and may still be capable of producing large, destructive avalanches.

Weather Forecast

Wednesday: Light flurries / Strong westerly winds / Alpine temperatures of about -13Thursday: 5-8cm of new snow / Moderate southerly winds / Alpine temperatures of about -10Friday: Overcast skies / Moderate westerly winds / Alpine temperatures of about -12

Confidence

Moderate - Due to the number of field observations

Avalanche Summary

There were no new reports of avalanche activity on Tuesday. An ACMG Mountain Conditions Report from Christmas day describes a slab avalanche failing on a steep, north facing slope at 2100m. The avalanche initially failed 40cm down from the surface, and then stepped down 110cm to the November crust. The size of the avalanche is unknown, but this speaks to the touchy nature of persistent slabs in the area. On Christmas eve, a skier was partially buried in a size 2 slab avalanche while skinning up a northeast facing slope at about 2000m. The failure plane of this avalanche is unknown although the depth (40cm) suggests the mid-December weak layer may have been the culprit. Check out the Mountain Information Network post for more details.

Snowpack Summary

Between 8-15cm of new snow has fallen in the past few days. Limited observations suggest there was little in the way of wind on Tuesday. However, strong winds forecast for Wednesday may redistribute the loose surface snow into new wind slabs in exposed higher elevation terrain. 20-50 cm of snow typically overlies the mid-December interface which consists of stiff wind affected snow, faceted (sugary) crystals, and surface hoar that formed in sheltered areas. The overlying slab appears to have a poor bond to these surfaces in some areas, especially in wind-affected terrain in the Dogtooth range and possibly Quartz Creek. In sheltered terrain, the overlying slab has remained soft. As it continues to settle and gain cohesion, we may start to see a more widespread persistent slab problem develop. The thick mid-November crust/ facet layer typically sits 70-140 cm down in the snowpack. Recent avalanche activity in the Dogtooth Range suggests this layer has woken up and has the potential for large avalanches. Check out this ACMG Mountain Conditions Report for more info: https://mountainconditions.com/reports/december-25th-dogtooth-range-november-crust-awakening

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