Boletín de aludes

Lizard-Flathead

Jan 22 – 23, 2023Avalanche Canada
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Archivado · caducó 4 years ago

Peligro de aludes

Tue
Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil

Lo esencial

Watch for wind slab reactivity as this problem continues to build.

The basal snowpack continues to demand thoughtful terrain selection to avoid triggering a very large avalanche.

Keep up the safe travel choices and avoid shallow rocky start zones.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible - Likely
    Tamaño
    1–1.5

    Elevated winds have likely formed wind slabs on leeward slopes along ridge crests at higher elevations. Expect any you encounter to remain reactive to human triggering on Sunday.

  • Deep Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    2–3

    Faceted grains make up the basal snowpack and are gaining strength very slowly. Where supportive to riders, a melt-freeze crust may be providing a bridging effect, making it more difficult to trigger deeper layers. Any avalanche triggered this deep will likely be large and destructive.

Confidence

Moderate

Avalanche Summary

Avalanche control with the use of explosives on Thursday, Friday, and Saturday produced several avalanches up to size 2 (large). These were from storm slabs and wind slabs. These instabilities and the deep persistent slab instability should be assumed to exist in the backcountry.

Snowpack Summary

Around 10 cm of recent snow has been redistributed into small wind slabs in exposed areas. It has been blending into older wind-affected surfaces above 1800 to 2000 m and settling on a crust below this elevation.

A crust/facet layer (2 to 15 cm thick at treeline elevation) is down 50 to 90 cm. Where it's thickest, it caps the settled and consolidated mid-snowpack.

Another crust/facet layer is down 70 to 150 cm. Below this crust, the basal snowpack is weak and faceted. The total snowpack depth ranges between 120 and 250 cm.

Weather Summary

Saturday Night

Cloudy, 2 to 5 cm accumulation, 10 to 20 km/h southwest wind gusting to 50, temperature dipping to -8 C.

Sunday

Cloudy, up to 8 cm accumulation with a chance of snow showers, 10 to 15 km/h west winds, temperatures reaching -3 C.

Monday

Cloudy, up to 4 cm accumulation, 15 km/h northwest wind gusting to 35, temperatures -8 to -4 C.

Tuesday

Cloudy with sunny breaks, trace accumulation, 15 km/h southwest wind gusting to 40, temperatures -10 to -5 C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.

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