Avalanche forecast

Sea To Sky

Nov 26 – 27, 2016Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

The region has just received well over a metre of snow, and destructive avalanches are still a real possibility. Give the snowpack time to gain strength before pushing into steep terrain.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Strong winds and heavy snowfall have been the perfect combo for large cornice development. To avoid a nasty ride, give fresh cornices a wide berth while traveling on ridgetops.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    Even if the storm tapers-off on Sunday, storm slabs may remain touchy, especially on higher elevation, wind-exposed features. I'd give the snowpack time to settle and gain strength before pushing into steeper terrain.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Sunday: 5-15cm of new snow / Moderate to strong southwest ridgetop winds / Freezing level at 900m. Monday and Tuesday: Mix of sun and cloud / Light and variable winds / Freezing level at about 900m

Avalanche Summary

In recent days, widespread storm slab avalanche activity was triggered naturally or with explosives. Most of the avalanches observed were in the size 2 range; however, a few size 3 and 3.5 avalanches were observed running in large, lee alpine features. With ongoing snow and wind on Saturday and Sunday afternoon, I'd be on the look-out for continued destructive storm slab activity, especially in higher elevation lee terrain.

Snowpack Summary

With ongoing stormy weather, snow depths have increased rapidly over the past week bringing treeline snow depths to 180-220 cm. Much of the snow from Wednesday and Thursday has settled and gained significant strength. That said, more recent systems have created large and reactive storm slabs which appear to be especially touchy in higher, wind-exposed terrain. Over a metre below the surface you'll find the thick mid-November crust. The reports we've received suggest a reasonable bond at this interface. Below this, the snowpack is reported to be strong and well-consolidated. A significant change from even a week ago is that we are now above threshold for avalanches below treeline (think cutblocks and open areas in the forest), so heads up as you work your way towards treeline. Nice to see mid-week posts to the Mountain Information Network... all observations are useful so please keep 'em coming!

Regions covered