Avalanche forecast

Sea To Sky

Jan 24 – 25, 2016Avalanche Canada
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Avalanche danger

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

It looks like one more dry day before the next round of warm storms hit the Coast this week.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Previously strong southerly winds created pockets of dense wind slab in exposed lee and cross-loaded terrain. 

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–3
    Cornices are becoming large and may fail naturally or under the weight of a person or snowmobile. 

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–5
    Two layers of buried surface hoar could still be found down 100-150 cm deep. Triggering may still be possible with heavy loads in specific features (slopes near treeline that did not previously slide).

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Monday: Cloudy with flurries. The freezing level rises to 1200-1400 m and winds are light or moderate from the S-SW. Tuesday: Periods of snow – 15-25 cm. The freezing level is around 1400-1600 m. Winds increase to moderate or strong from the SW. Wednesday: Moderate to heavy snow or rain. The freezing level spikes to around 2000 m and winds remain strong from the S-SW.

Avalanche Summary

No new natural avalanche activity was observed on Saturday. Explosives control produced mostly small (size 1) storm slabs with a couple deeper size 2 slabs from steep rocky slopes. Clear weather gave a better picture of the widespread natural cycle on Thursday and Friday. Most observers reported numerous size 2-3 slabs from all aspects and elevations. Many of these slabs released on the mid-January surface hoar, released on relatively low angle slopes, and showed very wide propagation.

Snowpack Summary

The "Pineapple Express Light" dumped 80-160 mm of precipitation on the South Coast this week. Most of this fell as snow above 1800-2000 m (over 1 m) with mixed rain and snow or just heavy rain below 1800 m. Heavy snow and strong winds have formed deep and dense wind slabs in exposed lee terrain and caused substantial cornice growth. Expect to find a rain crust at or near the surface (below 10-20 cm of fresh snow) at lower elevations. The early and mid-January surface hoar layers may have been wiped out by the storm and subsequent avalanche cycle. These layers would be down between 100 and 150 cm deep now. Tread cautiously until we know more about the state of these persistent weaknesses. The mid and lower snowpack is generally strong, with the exception of shallower snowpack areas that may be more faceted.

Regions covered