Avalanche forecast

Northwest Coastal

Dec 12 – 13, 2019Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low

Highlights

Human triggered slab avalanches are possible on slopes loaded by new snow and wind.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Expect new snow and wind to form fresh wind slabs over the next few days. Even thin wind slabs could be very reactive and propagate widely because the new snow is burying large surface hoar crystals.

Confidence

Moderate - Uncertainty is due to the track & intensity of the incoming weather system.

Weather Forecast

WEDNESDAY NIGHT: 10-20 cm of snow, 60 km/h wind from the south, alpine temperatures drop to -6 C.

THURSDAY: 5-10 cm of new snow, 40 km/h wind from the southwest, alpine high temperatures around -4 C.

FRIDAY: Another 10-15 cm of new snow by midday then clearing in the afternoon, 30 km/h wind from the southwest, alpine high temperatures around -4 C.

SATURDAY: Mix of sun and cloud, light wind, alpine high temperatures around -6 C. 

Avalanche Summary

No recent avalanches have been reported. Looking ahead, the main concern is new slabs forming above the surface hoar crystals that current sit on top of the snowpack. Over the next few days the likelihood of triggering storm slab or wind slab avalanches will increase as snow accumulates above this layer.

Snowpack Summary

Incoming stormy weather will bury a concerning layer of surface hoar that has formed in areas sheltered from the wind. As snow accumulates above this layer expect to find very reactive slabs. Reports suggest this layer can be found on all aspects up to treeline elevations. In the alpine, the new snow will bury hard wind slabs and sun crusts on south-facing terrain. The lower snowpack is generally considered strong and settled, as there has been very little to report in terms of recent avalanche activity or snowpack test results on deeper layers. Snowpack depths at treeline likely range from 90-160 cm and taper quickly at lower elevations.

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