Bollettino valanghe

Yukon

Apr 12 – 13, 2023Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 3 years ago

Pericolo valanghe

Fri
Sat
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
Senza grado
Apri la mappa completa

In sintesi

Lingering wind slabs may remain reactive to human triggers on lee aspects in the alpine.

Watch for recently formed and reactive wind slabs as you transition into wind affected terrain.

Problemi valanghivi

  • Wind Slabs

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

    Lingering wind slabs may remain reactive to human triggers on lee aspects in the alpine.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2–3

    A layer of facets sitting on a crust buried in January has recently been reactive. Triggering is most likely in areas where the snowpack is thin and weak, or with a heavy load like a cornice fall or the weight of a smaller avalanche in motion triggering this deeper layer.

Confidence

Moderate

Avalanche Summary

A size 2, cornice triggered wind slab was reported on a north aspect in the alpine on Sunday. See MIN

On Saturday a rider triggered a cornice fall from a distance, which produced a size 3 persistent slab avalanche on a northeast aspect at 1750 m. The avalanche was 200 cm deep and was suspected of having failed on the layer of facets above a crust buried in January.

Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.

Snowpack Summary

20-30 cm of recent soft snow may have seen some redistribution by recent wind but above 1200 m, it remains largely available for wind transport. Below 1200 m, moist snow or a thin crust may exist at or near the surface.

The new snow sits over previously wind-affected snow on north and east facing slopes and a crust on south facing slopes.

A weak layer of surface hoar/crust/facets buried in early January is now buried over 1 m deep in most areas. This layer has produced recent avalanche activity and remains a concern in terrain where the snowpack is thin. The lower snowpack consists of basal facets, particularly in shallow areas.

Weather Summary

Wednesday night

Cloudy with isolated flurries; 0-5 cm / 20 km/h south ridgetop wind / Temperature at treeline around -8 C / Freezing level valley bottom

Thursday

Mostly cloudy with isolated flurries; 0-3 cm / 20 km/h southwest ridgetop wind / Temperature at treeline around -5 C / Freezing level 800 m

Friday

Mostly sunny / 10 km/h east ridgetop wind / Temperature at treeline around -5 C / Freezing level 900 m

Saturday

Cloudy with flurries; 3-10 cm / 15 km/h east ridgetop wind / Temperature at treeline around -4 C / Freezing level 1000 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Cornice failure may trigger large avalanches.
  • Use caution on large alpine slopes, especially around thin areas that may propagate to deeper instabilities.

Regioni coperte