Bollettino valanghe

South Rockies

Jan 3 – 4, 2021Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 6 years ago

Pericolo valanghe

Tue
Wed
Alta quota
4 · Forte
Limite del bosco
4 · Forte
Sotto il limite
3 · Marcato
Apri la mappa completa

In sintesi

Avalanche danger will rise as a storm crosses the region over Saturday night through Sunday. There's uncertainty in the forecast, so gather info as you travel and step back from avalanche terrain altogether if new snow accumulations in your area reach 20 cm or more.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–3

    A hard melt-freeze crust is found around 50 to 100 cm deep. The concern is where weak layers of surface hoar and/or faceted grains exist above the crust. For areas where either of these weak layers exists above the crust, the possibility remains that riders could trigger large avalanches. The potential of triggering these layers will increase during this weekend's stormy period.

  • Storm Slabs

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

    10-30 cm of new snow, strong southwest wind, and an increasing freezing level are in the forecast for Sunday. Expect to find touchy new wind slabs adjacent to ridges, particularly in alpine terrain. Where new snow totals exceed 20 cm, expect a more widespread storm slab problem affecting avalanche terrain on all aspects and elevations.

Avalanche Summary

No recent avalanches have been reported in the region. Avalanche activity is expected to increase on Sunday. Riders could trigger storm or wind slabs and the possibility of triggering larger, more destructive avalanches involving deeper weak layers will be increased.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

SATURDAY NIGHT: Cloudy with snowfall bringing 5 to 15 cm of new snow. Moderate southwest wind, becoming strong at ridgetop.

SUNDAY: Cloudy with continuing flurries bringing another 5-15 cm of new snow, easing by evening. Moderate southwest winds, strongest in the morning. Alpine high temperatures around -4, cooling over the day. Freezing levels beginning near 1700 metres and falling over the day.

MONDAY: Mainly cloudy with isolated flurries and a trace of new snow, increasing a bit overnight. Moderate southwest winds. Alpine high temperatures around -4 with freezing levels rising to about 1500 metres.

TUESDAY: Cloud and flurries diminishing over the day with 5-10 cm new snow, including overnight accumulations. Light southwest winds. Alpine high temperatures around -5 with freezing levels around 1500 metres.

Snowpack Summary

Another 10 to 30 cm of snow is forecast to accumulate by Sunday afternoon with associated strong southwest wind. New storm slabs are expected to form in sheltered terrain and wind slabs in exposed terrain features.

Weak layers of feather surface hoar and/or sugary faceted grains may be found above a hard melt-freeze crust around 50 to 100 cm deep. The most recent avalanche activity on these layers were reported on December 23 and 25.

The base of the snowpack consists of faceted grains and a hard melt-freeze crust from early-November. The most recent activity on this layer was on December 23. The likelihood of avalanche activity at these deeper layers will be heightened during and immediately after the storm.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid slopes that sound hollow or drum-like.
  • Be aware of the potential for large avalanches due to the presence of buried weak layers.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Regioni coperte