Bollettino valanghe

Kootenay Boundary

Dec 20 – 21, 2022Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 4 years ago

Pericolo valanghe

Thu
Fri
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Manage your terrain and keep an eye out for the persistent slab problem as you enjoy the fresh snow.

Signs of instability like whumpfing and shooting cracks are a clear indication to back off for the time being.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    There are now two persistent weak layers within the snowpack.

    A 35 - 45 cm soft slab sits above a weak layer of surface hoar on shaded aspects and crust on steep solar aspects.

    A second weak layer of surface hoar and facets from mid-November is buried down 50 to 80cm in the region.

    While avalanche activity has tapered off on these layers they likely remain rider triggerable in specific sheltered terrain features at treeline and below.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Low density snow continues to accumulate on a wide variety of surfaces where bonding is not likely to occur. Moderate wind that is to accompany this new snow is likely to redistribute this snow and create fresh wind slabs.

    Beware of smaller loose dry avalanches building a load big enough to trigger weak buried layers and creating larger avalanches.

Confidence

Moderate

Avalanche Summary

No new avalanches reported in the last 24 hours other than some minor sluffing.

Avalanche activity is tapering off what it was last week when the mid-November layer was very reactive, producing large avalanches in our region and that of our neighbours'. This layer should still be a concern and can be triggered in areas with a shallow snowpack or in certain terrain such as convex rolls.

Snowpack Summary

The top 10 to 25 cm of our snowpack is of low-density unconsolidated snow that sits on a buried surface hoar layer in sheltered areas and a sun crust on the solar aspect. The snow becomes slightly more consolidated after these layers until 35 to 45 cm below the surface is reached where another weak, created in early December, can be found. This layer is made up of surface hoar in sheltered areas and a thin sun crust in open south-facing terrain.

The layer that is still the main concern, is that of mid-November. It is made up of large surface hoar crystals, facets, and a melt-freeze crust and can be found up to 80 cm deep. This layer has been reactive at treeline between 1700 to 2200 m, on all aspects.

Below the mid-November layer is a generally weak, faceted snowpack. Snowpack depths average 80 to 160 cm in the alpine.

Weather Summary

Monday Night

Cloudy with clear periods, no accumulation, 10 to 20 km/h southwest wind, -22 C at 1500 m.

Tuesday

Mostly cloudy, up to 13 cm accumulation, 15 km/h south winds, -21 C at 1500 m.

Wednesday

Mostly sunny with cloudy periods, no accumulation, 15 to 22 km/h northeast wind, temperature -25 C at 1500 m.

Thursday

Sunny, no accumulation, 10 km/h south winds, -23 C at 1500 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
  • Don't let the desire for deep powder pull you into high consequence terrain.
  • If triggered, loose dry avalanches may step down to deeper layers resulting in large avalanches.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Regioni coperte