Bulletin d’avalanche

Northwest Inland

Feb 14 – 15, 2016Avalanche Canada
Voir sur la carte
Archivé · expiré 11 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible

Points saillants

Benign weather on Monday should lower the hazard throughout most of the region.The hazard may be higher than posted in the far north of the region where buried weak layers may still be reactive to human-triggering.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–3
    Recent snow and strong winds have formed wind slabs on mainly north to easterly aspects at treeline and in the alpine.
  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    3–6
    Buried weak layers are still reactive in the snowpack, especially in the far north of region, and have the potential to produce very large avalanches. Thin spot triggering, cornice releases, and smaller avalanches all have the potential to step down.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain on Tuesday

Weather Forecast

A ridge of high pressure is expected to keep the region mostly dry on Monday. Freezing levels are expected to stay below 900m with light alpine winds. A storm system is expected to reach the region on Monday evening or overnight and should continue through Tuesday. 5-15cm is expected between Monday evening and Tuesday afternoon. Freezing levels are forecast to reach around 1000m and alpine winds are forecast to be moderate from the southwest. Wednesday is expected to be mainly dry with freezing levels below 700m and light alpine winds.

Avalanche Summary

On Saturday, a natural size 1.5 wind slab avalanche was reported on a west aspect at 2200m elevation which was 20cm thick. No new avalanches were reported on Friday. On Thursday in the far north of the region, a skier accidently triggered a size 2 persistent slab avalanche on a northwest aspect at 1650m and explosives triggered a size 2.5 persistent slab on a northeast aspect at 1400m. These both failed on the early January surface hoar layer down 100-150cm. Wind slabs are expected to remain reactive to human-triggering on Monday in steep, unsupported leeward features and around loaded convexities.  In the far north, deeply buried persistent weak layers may still be reactive to large triggers.

Snowpack Summary

Recent snowfall and mostly southwestern winds have formed wind slabs in the leeward features in the alpine and at treeline. Storm snow from last week has settled due to recent warm temperatures. There may be a buried layer of surface hoar in the top 30 cm of the snowpack from early February, this layer was found at Hankin, but has not been widely reported. Crusts may be developing at mid-elevations as the freezing level slowly descends. The early January persistent weak layer of buried surface hoar is down 50-80 cm in most of the region, but may be down a metre or more in the deeper snowpack areas in the southwest of the region. Shallow snowpack areas in the east and north of the region may have a weak base layer of facetted snow on or just above the ground.

Régions couvertes