Avalanche forecast

Kootenay Boundary

Dec 7, 2017Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

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

Avoid south slopes. They have been wind loaded and will become weak with the intense warming and sun.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Winds from the northwest have formed hard slabs on south and east facing slopes. Be careful on steep convex terrain or where the wind has blown the snow into more cohesive slabs.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Conditions will be more like spring than winter starting Wednesday. Surface snow layers can become weak when hit by the sun. Minimize your exposure to terrain traps - even small sluffs can push you into dangerous terrain.

Confidence

High - The weather pattern is stable

Weather Forecast

THURSDAY: Alpine sun with some valley clouds, light northwest wind, freezing level around 3300 m with inversions in the valleys.FRIDAY: Alpine sun with some valley clouds, light northwest wind, freezing level around 3000 m with inversions in the valleys.SATURDAY: Increasing cloud, moderate west wind, freezing level around 2700 m with inversions in the valleys.

Avalanche Summary

On Tuesday, a small (size 1) natural storm slab avalanche was reported on a southeast slope at 2150 m. Previous activity from the weekend included some larger natural and skier triggered storm slabs up to size 2, with the largest cause by recent loading from northwest winds.

Snowpack Summary

Dramatic warming will cause widespread melting of the surface snow, especially on south-facing slopes. Crusts may form overnight, but will melt quickly in the mornings. 30 - 50 cm of new snow has fallen in the past week. At higher elevations, northwest winds redistributed the snow, forming wind slabs on downwind (lee) features. Below the recent storm snow you'll likely find a couple of widespread crusts (2 to 5 cm thick) which formed as a result of late November's rain. The depth of the snowpack varies greatly with elevation. Recent reports suggest the average depth is 100-170 cm in the alpine, 50-100 cm at treeline, and decreasing rapidly below treeline where the primary hazards are rocks, stumps, and open creeks.

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