Boletín de aludes

Kootenay Boundary

Feb 28 – Mar 1, 2022Avalanche Canada
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Archivado · caducó 5 years ago

Peligro de aludes

Wed
Thu
Alta montaña
4 · Fuerte
Límite del bosque
4 · Fuerte
Bajo el límite
3 · Notable
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Lo esencial

Avalanche danger will increase throughout the day with heavy snowfall, southwest wind and rising freezing levels. 

Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–3.5

    Two buried persistent weak layers are expected to create problems as the new storm snow accumulates. 

    A weak layer from mid-February was down 20-30 cm prior to the storm and is expected to become reactive as the overlying snow forms a thicker and more cohesive slab. 

    Two weak layers of surface hoar from January were down 40-70 cm prior to the storm and were primarily a concern in the east of the region on northerly aspects around treeline. Smaller storm avalanches have the potential to step down to these deeper layers. 

  • Storm Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Very Likely
    Tamaño
    1.5–3

    Ongoing snowfall, strong southwest wind and rising freezing levels will combine to increase avalanche danger throughout the day.

    Storm slabs will become increasingly sensitive to human triggering and a natural avalanche cycle will begin as snow stacks up. Avoiding avalanche terrain and staying clear of overhead hazard is the best way to stay safe during periods of heavy snow accumulation.

Confidence

Moderate - We are confident the likelihood of avalanche will increase with the arrival of the forecast weather. Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

There is some model disagreement around the timing and intensity of the next system. 

Sunday night: Snowfall 10-15 cm, moderate to strong southwest wind, treeline low around -5 °C.

Monday: Snowfall 20-35 cm, moderate to strong southwest wind, treeline high around 0 °C, freezing levels climbing rapidly and could reach over 2000 m by late Monday night.

Monday night: Heavy precipitation continues overnight with 20-40 mm possible with strong southwest wind. Freezing levels around 2000 m.

Tuesday: Snowfall easing during the day, moderate to strong SW wind, freezing levels dropping slightly to 1800 m.

Wednesday: Light snowfall, light to moderate southwest wind, treeline high hovering around zero.

Avalanche Summary

On Saturday a skier remotely triggered a large (size 2) wind slab over a crust just north of the region. Last week riders triggered wind slabs, as well as at least two size 2 persistent slabs involving the mid-January surface hoar layers in the east of the region.

Snowpack Summary

By the end of the day on Monday new storm slabs will have buried highly variable snow surfaces which include wind-affected surfaces in exposed terrain, a thin sun crust on solar aspects which may be faceting, surface hoar in sheltered areas, and/or old storm snow on shaded slopes which may be faceting. 

A weak interface from mid-February was down around 20-30 cm prior to the storm. It consists of a sun crust on solar aspects, facets, and/or surface hoar. This layer was previously only reactive in wind-loaded terrain where a slab had formed but it is expected to become a more widespread problem as the storm progresses and creates a more widespread slab.

Two layers of buried surface hoar from January were down around 40-70 cm prior to the storm. Most recently, this surface hoar was most reactive in sheltered areas around treeline in the east of the region, and appeared to be dormant through the rest of the region. As the storm progresses and more load is added to the snowpack, this surface hoar will get tested and avalanches have the potential to step down to these deeper layers. 

Terrain and Travel

  • Storm slab size and sensitivity to triggering will likely increase through the day.
  • Avoid all avalanche terrain during periods of heavy snowfall.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Regiones cubiertas