Bulletin d’avalanche

Lizard-Flathead

Mar 26 – 27, 2021Avalanche Canada
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Archivé · expiré 6 years ago

Danger d’avalanche

Sun
Mon
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible

Points saillants

Watch for pockets of wind slab at higher elevations. Seek out sheltered, north facing terrain for the best snow quality. 

Avoid steep, sun exposed slopes during the heat of the day as brief sunny periods can significantly weaken the snowpack at this time of year.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Watch for wind-loaded pockets in lee terrain features such as beneath ridge crests and roll-overs.

    Cornices are large and need to be given space from above and below.

Weather Forecast

FRIDAY NIGHT - Mainly cloudy / moderate west wind / alpine low temperature near -5 

SATURDAY - Mainly cloudy with isolated flurries / moderate to strong west wind / alpine high temperature near -4 / freezing level 2100 m

SUNDAY - Snow, 20 cm, with another 10-15 cm overnight / strong southwest wind / alpine high temperature near -1 / freezing level 1800 m

MONDAY - Cloudy with flurries, 10 cm / light northwest wind / alpine high temperature near -8

Avalanche Summary

On Friday, at the time of publishing, there were a few reports of size 1 human triggered storm slab avalanches on north aspects in the alpine.

On Thursday there were a few reports of natural size 1.5-2 storm slab avalanches, as well as a size 1.5 explosive-triggered cornice.

On Wednesday there were reports of human-triggered dry loose avalanches on steep northerly aspects. Explosive control work on Monday and Tuesday produced mainly size 1 dry loose avalanches and a few size 1-1.5 storm slabs.

A large (size 2) glide slab occurred overnight last Friday on a lower elevation slope on Mt. Fernie. It may have been coaxed into action by overnight rainfall. This serves as a great reminder to avoid slopes with glide cracks on them at all times. They are inherently unstable and can release at any time.

Snowpack Summary

20-40 cm of new snow has accumulated incrementally over recent days. Depending on the time of day, moist snow or a crust can be found on solar aspects and below 1700 m. Isolated, soft wind slabs can be found in lee features of wind exposed alpine terrain. The snowpack is otherwise well settled and strong.

Terrain and Travel

  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Remember that in the spring strong solar radiation and warm temperatures can weaken the snow in a matter of minutes.
  • Avoid steep slopes when air temperatures are warm, or solar radiation is strong.

Confidence

High - Confidence is due to a stable weather pattern with little change expected.

Régions couvertes