Bulletin d’avalanche

Lizard-Flathead

Dec 12 – 13, 2019Avalanche Canada
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Archivé · expiré 7 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    10-20 cm of new snow with strong wind from the west will form fresh wind slabs in alpine terrain and around ridgetops.

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely - Possible
    Taille
    1.5–3

    The likelihood of triggering a large avalanche on one of the crusts and weak layers in the lower snowpack is gradually reducing, but the consequence is high. Avoid steep and complex terrain while these layers are being loaded by new snow and wind.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

WEDNESDAY NIGHT: Light flurries bring 5-10 cm of new snow, 50 km/h wind from the southwest, alpine temperatures around -6 C.

THURSDAY: Scattered flurries throughout the day with 5-10 cm of new snow, 50 km/h wind from the west, alpine high temperatures around -2 C.

FRIDAY: 5-10 cm of new snow possible by the morning and then cloudy in the afternoon, 30 km/h wind from the west, alpine high temperatures around -4 C.

SATURDAY: Mostly cloudy, 30 km/h wind from the west, alpine high temperatures around -6 C.

Avalanche Summary

Recent avalanche activity is limited to a few small wind slab avalanches (size 1) triggered with explosives on Wednesday. Avalanche activity has seemed to quiet down since the weekend, when numerous large persistent slab avalanches (size 2-3) were reported at treeline and alpine elevations. Many of these avalanches ran on the November and October crust layers 40-100 cm deep. Triggering an avalanche on one of these deeper layers is still a possibility in steep rocky terrain.

Snowpack Summary

New snow and wind will likely form fresh wind slabs at upper elevations. In sheltered areas 30-40 cm of snow from last weekend is gradually settling. Crust layers from November and October can be found 40-100 cm below the surface and have recently produced large avalanches with explosive triggers, but the likelihood of human triggering is gradually reducing. Snowpack depths range between 50-100 cm at higher elevations and taper rapidly below treeline.

Régions couvertes