Avalanche forecast

South Coast Inland

Jan 2, 2018Avalanche Canada
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Avalanche danger

Wed
Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Continued warm temperatures should allow the snowpack to further settle and stabilize, but small storm slabs in more extreme terrain may still be an issue. Watch for the odd loose wet avalanche on steep solar aspects in the afternoon too.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Aided by wind, time and warmth, the storm snow is settling into a more cohesive slab. For the most part, this slab is bonding well to the underlying surface, but don't be too cavalier with your decision making, warming temps may change its behavior.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Natural loose wet avalanches remain possible Tuesday, especially on steep sun exposed slopes. With all the new snow in the last few days loose wet avalanches could entrain considerable mass, especially in terrain traps like gulleys.

Confidence

Moderate -

Weather Forecast

This week will see a complete reversal in the weather pattern as warmer temperatures and dry conditions are expected to dominate. Warmer air aloft will prevail as an off shore upper ridge pushes inland and the flow aloft switches from cold northwesterly to mild southwesterly. This warm dry period is expected to persist through Friday.TUESDAY: A few clouds in the morning, cloud cover building to broken in the afternoon. Temperature Inversion with below freezing air in the valley, above freezing (warmer) air between 2000 m and about 3000 m. Alpine temperatures could rise as high as +5 c, light northwest wind, no snow expected.WEDNESAY: Scattered cloud, Temperature Inversion with below freezing air in the valley, above freezing (warmer) air between 1500 m and about 2500 m, light southwest wind, no snow expected.THURSAY: Scattered cloud, freezing level at about 1000 m, with a Temperature Inversion allowing for above freezing (warmer) air between 1500 m and about 2500 m, light southwest wind, no precipitation expected during the day, potential for very light rain/snow on Thursday night.

Avalanche Summary

On Sunday isolated soft slabs were reported from steep features, gully walls and convex rolls on south and southwest facing terrain to size 1. Isolated loose avalanches to size 1 from steep solar facing terrain were also reported. On Saturday a widespread avalanche cycle to size 1.5 was reported with avalanches failing within the recent storm snow.

Snowpack Summary

On Sunday a slight crust began to form on south and southwest facing aspects as warm temperatures and sun combined to moisten the snow surface. Cooler north and east facing features remain cold and dry. Last Thursday and Friday two successive storms produced 50 to 80 cm of snow with wind mainly out of the south. The new snow rests on a variety of old surfaces including crust on solar aspects, old wind slabs, facets and isolated surface hoar below treeline, but avalanche activity on this interface continues to decrease as time and warm temperatures allow the old storm snow to settle and gain cohesion. Wind effect in the alpine has been widely reported but wind slab activity has been limited to the usual suspect places as per the activity discussion above.A widespread melt-freeze crust buried mid-December exits throughout the region. This crust is down around 30 to 60 cm in the Duffey. Around the Coquihalla it's about 100 cm below the surface. This layer has not produced much in the way of avalanche activity and is likely trending towards dormancy. Beneath the mid-December crust, the lower snowpack is generally strong and well settled.

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