Bollettino valanghe

Northwest Inland

Nov 30, 2017Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 9 years ago

Pericolo valanghe

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

In sintesi

Be aware of wind slabs at upper elevations as well as a weak layer deep in the snowpack. This layer has produced recent large avalanches and may be triggered by a wind slab release or from a shallow snowpack area.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2
    Recent snow and wind have formed touchy wind slabs. Expect these slabs to be more pronounced at higher elevations. Watch for signs of wind affected snow, whumpfing and cracking.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible - Likely
    Dimensione
    2–3
    The late October crust lies near the base of the snowpack with a thin layer of weak, sugary snow above it. This layer may react to a heavy trigger like a storm slab release and can also be triggered from shallow snowpack areas.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: Isolated flurries, accumulation 5-10 cm. Moderate southwest wind. Alpine temperature -6. Freezing level 500 m.FRIDAY: Isolated flurries, accumulation 5-10 cm. Light to moderate southwest wind. Alpine temperature -7. Freezing level 500 m.Saturday: Mix of sun and cloud. Light west wind. Alpine temperature -10. Freezing level 300 m.

Avalanche Summary

Skiers in the Seaton area on Tuesday reported remotely triggering a large (Size 2.5) avalanche from 150 m away as they approached a north-facing, treeline bowl. The avalanche was triggered from a shallow snowpack area and failed on a weak layer of sugary, snow crystals just above the late October crust near the base of the snowpack. Last week several estimated Size 2.5-3 avalanches were observed on the Kathlyn face of Hudson Bay Mountain and are also suspected to have failed on the late October crust. This "crust/facet combo" layer is capable of producing very large avalanche and is expected to remain a layer of concern for some time. Please post your observations to the Mountain Information Network. (MIN)

Snowpack Summary

Snowpack depths over the south of the region average 100-140 cm at treeline elevations, and up to 160 cm in the alpine. Approximately 30-40 cm of recent snow now overlies the supportive November 23 crust that formed last week and is suspected to extended well into alpine elevations. Below this crust is well settled snow and the widespread late October crust, which is present near the base of the snowpack at all elevations and features a layer of weak, sugary grains above it. This late October "crust/facet combo" layer has been reported as the failure layer for recent large avalanches, and has also been producing moderate, sudden compression test results in snowpack tests. This layer will remain a concern for the potential of a slab release to step down to this layer as well as the potential for large propagations triggered from shallow snowpack areas.

Regioni coperte