Avalanche forecast

South Coast Inland

Dec 16, 2018Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Mon
Tue
Alpine
4 · High
Treeline
4 · High
Below
2 · Moderate
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Highlights

Incoming storms will drive the avalanche hazard for the next few days. The days for playing it safe and conservative continue!

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–3
    A weak layer buried approximately 70 cm below the surface has the potential to produce large avalanches. And, it's only going to get deeper with even bigger avalanches possible ...

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5
    Forecast new snow amounts of up to 50 cm by Sunday evening will rapidly increase avalanche hazard.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

SATURDAY NIGHT: 20 to 30 cm new snow in places like the Coquihalla, I expect a little less further north (e.g. Duffy Lake). Freezing level around 800 m. Moderate southerly winds.SUNDAY: Another 20 to 30 cm new snow. Freezing level around 1700 m. Moderate to strong southerly winds.MONDAY: Continued snow with an additional 15 to 25 cm of snow. Freezing level around 1500 m. Moderate southwesterly winds.TUESDAY: Storm continues with more snow, possible as much as 25 cm. Freezing level steady around 1500 m. Moderate to strong southwest winds.

Avalanche Summary

Explosive control work along the Duffey Lake road on Friday produced avalanches up to size 2.5 running on the weak layer of facets buried 60 to 80 cm below the surface. A remotely triggered size 1.5 avalanche in the Coquihalla Summit backcountry suggests this same layer is a concern there.

Snowpack Summary

Up to 1 m of new snow fell since the storm pattern started last Sunday. Strong southerly winds distributed new snow into variable wind slabs in exposed locations. A crust at or near the surface likely exists up to approximately 1700 m.Below the recent storm snow lies a weak layer, comprising 20-30 cm of low density faceted snow. Initially, the snow did not bond well to this layer. While it's likely gaining strength, field observations show that slab avalanches remain possible on this layer.Near the base of the snowpack, a crust exists that previously had sugary facets. This could potentially still be of concern in high north facing areas in drier parts of the region. Elsewhere, this layer is no longer a concern.

Regions covered