Avalanche forecast

South Coast Inland

Feb 15, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

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

Highlights

Wind slabs exist on a wide range of aspects and may be hidden by the most recent snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Reactive wind slabs exist, especially around ridge crests where more wind loading has occurred. Recent shifting wind patterns have formed slabs on a wide range of aspects.
  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–3.5
    Large, looming cornices have formed along ridgelines. They need to be given an extra wide berth from above and below. A large cornice collapse in the north of the region may have the ability to trigger a deeply buried weak layer.

Confidence

High -

Weather Forecast

THURSDAY: Increasing cloud with light flurries in the evening, moderate to strong northwest wind, alpine high temperatures around -10 C in the north and -6 C in the south.FRIDAY: Flurries easing throughout the day with 5-10 cm of new snow in the south and trace amounts in the north, moderate to strong northwest wind, alpine high temperatures around -8 C in the north and -4 C in the south.SATURDAY: Moderate snowfall with 10-25 cm throughout the day, strong southwest wind, alpine high temperatures around -8 C in the north and -4 C in the south.

Avalanche Summary

No new avalanches were observed in the Coquihalla area on Wednesday, while several size 2 wind slabs (40 cm thick) were triggered with explosives on south-facing slopes in the Duffey area. On Tuesday, a small (size 1) wind slab was triggered by a skier on a small west facing feature in the northern part of the region.Reports from the weekend included numerous small wind slabs releasing with skier traffic on steep treeline and alpine features, as well as a few large (size 2-3) naturally triggered slabs in the northern part of the region (some of which were triggered by cornices).

Snowpack Summary

10-20 cm of new snow sits above a variety of old interfaces, including unconsolidated snow in sheltered areas, scoured and wind loaded snow in exposed areas, and a melt-freeze crust below roughly 1900 m. Storm snow amounts from the past week are roughly 60 cm in the south of the region and about half this amount in the north of the region. About 80-150 cm down in the mid snowpack sits the mid-January crust. It generally shows signs of bonding to the overlying snow but will likely remain sensitive to large triggers - especially in thinner snowpack areas. Large, looming cornices exist, they are fragile, and they demand respect. Cornice falls are very effective triggers for avalanches on the slopes below them.

Regions covered