Bollettino valanghe

Purcells

Feb 11 – 12, 2023Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 4 years ago

Pericolo valanghe

Mon
Tue
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

The message remains the same – a complex, and generally weak snowpack is best managed by continuing to stick to lower angled, low consequence terrain. Every two or three days there is a report of a persistent slab or deep persistent slab avalanche.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Recent new snow combined with wind has formed fresh wind slabs in lee terrain features.

  • Persistent Slabs

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

    Several weak layers in the upper and middle portions of the snowpack are at prime depths for human triggering. Stay disciplined and choose low consequence lines. Use extra caution in steep, wind-sheltered terrain where buried surface hoar is most likely to be preserved.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    2.5–4

    It remans possible that riders could trigger a weak layer of facets near the base of the snowpack. The most likely area to trigger it is in shallow areas with variable snow depths. Avoid thin and rocky start zones and select routes that avoid traveling through or under large avalanche paths.

Confidence

Moderate

Avalanche Summary

On Friday in the central part of the region, there was a remotely triggered (from a distance) size 2 skier triggered persistent slab stepping down to deep persistent slab avalanche on a north aspect at 2400m.

On Wednesday there were two reports of natural deep persistent slab or persistent slab avalanches to size 3. These were viewed in the central part of the region and in the Dogtooth range. It seems both were triggered by heavy loads (cornice fall and wind slab avalanche stepping down) on north east and east aspects at 2500m.

There were also reports of wind slab avalanches to size 1.5 and 2.5 on north and east aspects in the alpine.

The possibility remains of triggering facets near the base of the snowpack, particularly on shallow, rocky slopes.

Snowpack Summary

20-50 cm of snow since late January has settled, or has been redistributed by predominantly west or southwest wind.

60-90 cm below the surface, the mid-pack contains a layer buried in early to mid January that remains a concern. It mostly exists as surface hoar, but facets or a crust may also be present.

A layer from late November is found 75 to 150 cm deep and is part of a generally weak, faceted snowpack.

Snowpack depths range between 90 and 200 cm at treeline, with the shallowest depths found on the eastern edge of the region.

Weather Summary

Friday Night

Mainly cloudy with clear periods. Moderate west ridgetop wind. Treeline temperature around -6 ºC.

Saturday

Mainly cloudy with sunny periods. Light to moderate west ridgetop wind. Treeline temperature around -4 ºC. Freezing level rising to 1100m.

Sunday

Mostly cloudy with isolated flurries. Light to moderate west and southwest ridgetop wind. Treeline temperature around -4 °C. Freezing level around 1200m.

Monday

Mainly cloudy with scattered flurries. Moderate southwest ridgetop wind. Treeline temperature around -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.
  • Approach lee and cross-loaded slopes with caution.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Uncertainty is best managed through conservative terrain choices at this time.

Regioni coperte