Bollettino valanghe

Banff Yoho Kootenay

Dec 14 – 15, 2022Avalanche Canada
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Archiviato · scaduto 4 years ago

Pericolo valanghe

Fri
Sat
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato

In sintesi

Consequences are still high if you trigger a deep persistent slab. Be prepared to make conservative route choices for the foreseeable future. See snowpack observations at Bow Summit today.

Problemi valanghivi

  • Wind Slabs

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

    10-25 cm of snow fell over the past week and moderate S-W winds formed wind slabs in lee areas. These slabs are relatively small but the major concern is that if triggered, these may step down to the weak basal facets resulting in larger avalanches.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    1–2.5

    A 20-60 cm slab has formed over the very weak basal facets, with thin crusts at the interface at lower elevations and on some solar slopes. Human triggering is likely on any steep slopes where a cohesive slab of snow is found. This problem will remain for the foreseeable future.

Confidence

Low

Avalanche Summary

Lake Louise patrol was knocking out hard wind slabs with explosives, that would gauge down to the ground and entrain facets. These slides were size 1.5 and all occurred in the alpine. Sunshine patrol was able to trigger one size 2 deep slab in previously uncontrolled terrain with explosives. As usual, it entrained facets as it progressed downslope.

Snowpack Summary

20-60 cm of snow has formed a slab over a very weak base consisting of facets. Thin crusts can be found on the facet interface at lower elevations and on solar slopes. Expect to find lingering wind slabs at higher elevations. Snowpack depths at treeline range between 60 and 120 cm.

Weather Summary

Relatively warm valley bottom temps of near zero, with the alpine around -10 on Wednesday. A small amount of precipitation is expected overnight Tuesday into Wednesday (2-4cm), Wind is expected to remain light from the NW on Wednesday. Overall, a benign weather pattern will persist with minimal inputs to the snowpack.

Terrain and Travel Advice

  • Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
  • Uncertainty is best managed through conservative terrain choices at this time.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Regioni coperte