Bulletin d’avalanche

Northwest Inland

Mar 23 – 24, 2017Avalanche Canada
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Archivé · expiré 10 years ago

Danger d’avalanche

Sat
Sun
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Points saillants

A persistent slab above a crust may take time to stabilize. Evaluate the terrain and snowpack carefully before committing to steeper terrain.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2
    A 20-60 cm thick slab above a rain crust has been reactive to human triggers over the past week. Most activity has been in wind-affected terrain. Persistent slabs also have the potential to step down to deep basal weaknesses near the ground.

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

FRIDAY: Unsettled weather with isolated flurries, moderate south wind, alpine temperature around -5 C.SATURDAY: More flurries with accumulations up to 5 cm, strong south wind, alpine temperature around -7 C.SUNDAY: Mix of sun and cloud, light southeast wind, alpine temperature around -7 C.

Avalanche Summary

Reports from Wednesday are limited to several size 1 loose wet avalanches running on a sun crust at lower elevations. On Tuesday, a skier near Hazelton remotely triggered a size 1 avalanche that subsequently triggered two other size 2 avalanches on a persistent weak layer (30 cm deep). The avalanches occurred on northeast aspects at 1400 m. On Monday, a size 3 slab avalanche was triggered by a cornice fall on a north aspect at 1700 m north of Kispiox. Over the weekend, several reports describe reactive slabs above a crust, including a size 2.5 snowmobile-triggered avalanche in the Telkwas and a size 2 skier-triggered wind slab north of Kispiox.The cooling trend should help stabilize the persistent slab, but human triggering is still possible in steep or unsupported terrain.

Snowpack Summary

Unsettled weather with moderate winds is redistributing snow in exposed terrain. Recent warming and sun have likely left a crust on solar aspects and below 1300 m. Recent snow has settled into a 20-60 cm thick slab above an older crust interface. Recent reports suggest the bond to the crust is poor and has resulted in a reactive slab. Weak sugary snow near the ground has been a dormant instability, but it may still be possible to trigger in steep rocky terrain.

Régions couvertes