Avalanche forecast

Northwest Coastal

Apr 7 – 8, 2018Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Mon
Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate

Highlights

Strong winds have formed widespread wind slabs at upper elevations.  Just how reactive these slabs are however, is a bit unknown. Be cautious in lee areas, start with small, low consequence features before working your way into bigger terrain.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Strong to extreme winds have formed touchy wind slabs in leeward areas in the alpine and exposed treeline features. While natural activity has tapered off, these slabs may remain primed for human triggering.
  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Recent storm snow may become unstable with rising freezing levels and solar radiation. Watch for moist or wet snow releases at lower elevations and on sunny slopes.

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

TONIGHT: Mostly cloudy. Ridge wind light to moderate, southeast. Alpine temperature near -1. Freezing level 1200 m.SUNDAY: Mix of sun and cloud. Ridge wind light, northwest. Alpine temperature near 0. Freezing level 1500 m. MONDAY: Cloudy, flurries. Accumulation 2-8 cm. Ridge wind moderate to strong, south. Alpine temperature near -2. Freezing level 1500 m.TUESDAY: Cloudy, flurries. Accumulation 6-12 cm. Ridge wind strong to extreme, south. Alpine temperature near -1. Freezing level 1500 m.

Avalanche Summary

There have been no reports of avalanche activity since Thursday when northern parts of the region saw a widespread natural avalanche cycle triggered by strong to extreme wind loading event in the alpine. There was also a report of an icefall triggered size 2.5 slab avalanche that failed on the mid-March interface, northwest of Meziadin Lake.Wednesday a natural avalanche cycle up to size 1.5 was reported on wind affected features, as well as skier triggered storm snow releases up to size 1. A natural cornice failure that released a size 1.5 slab was also reported from an east aspect in the Shames area. Read MIN report here.On Tuesday, there was a size 2 natural wind slab avalanche reported from a north aspect alpine slope. There were also several small (size 1), thin soft slab avalanches on recently wind-loaded features. A large (size 3) glide avalanche was reported from a N-NW slope below treeline. Additionally, steep south aspect slopes released loose wet avalanches in the afternoon.

Snowpack Summary

Strong to extreme winds have created widespread wind affect in the alpine and at treeline. At lower elevations up to 10-20 cm of snow sits on a solid crust.In the south of the region, 70 to 100 cm of recent storm snow overlies two layers of surface hoar. The layers are most prominent on north to east aspects and were buried early-March and mid-March. In the north of the region, these layers are around 40 cm deep.Bellow this interface the mid-pack is generally well-settled and strong. However, shallower parts of the region, such as the far north, have weak sugary facets near the bottom of the snowpack.

Regions covered