Avalanche forecast

South Coast Inland

Jan 31 – Feb 1, 2018Avalanche Canada
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Avalanche danger

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

New snow and wind will keep the avalanche danger elevated at higher elevations on Thursday, especially in the south of the region where forecast snowfall amounts are the greatest.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    New snow and wind on Wednesday night are expected to form new wind slabs in higher elevation lee terrain. This new snow overlies older storm slabs which are gaining strength but may remain sensitive to human triggering in steep, unsupported terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5
    Recent heavy snowfall and strong winds have created fragile new cornices. These monsters may surprise with nasty consequences. Use extra caution around ridge crests.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Wednesday

Weather Forecast

Wednesday Night: 10-15cm of new snow / Moderate to strong southwest winds / Freezing level at 800mThursday: 3-5cm of new snow / Light southwest winds / Freezing level at 900mFriday: 8-10cm of new snow / Light southwest winds / Freezing level at 1200mSaturday: Light flurries / Light and variable winds / Freezing level at 1200m

Avalanche Summary

On Monday 2 people were buried in a size 2 slab avalanche in Marriott Basin in the Duffey Lake area. The touring party was large and all victims were rescued successfully by their partners, but all gear was lost. Not much is known about the aspect, elevation or the weak layer associated with the avalanche.Looking forward, new snow and wind on Wednesday night is expected to promote a new round of wind slab activity in higher elevation lee terrain.

Snowpack Summary

Monday's continuing storm brought 20-40 cm of new snow to the surface above about 1700 metres with depths that increase with elevation. The greatest accumulations occurred in the south of the region, and the snowpack at lower elevations is now capped by a new rain crust and only light new snow amounts. At higher elevations, strong southerly winds have redistributed the new snow forming deep deposits and cornices in leeward terrain. Storm snow totals since mid-January have reached about 150 cm.Below this depth, you'll likely find a few crusts that were buried during the first few weeks of January. Due to limited observations, not much is known about the current reactivity of these layers.The lower snowpack includes the more well-documented mid-December crust layer. Persistent slab avalanche activity from the Whistler area late last week suggests that heavy triggers like a large storm slab or cornice release may carry the risk of triggering this layer in isolated terrain - particularly in the north of the region where it has shown prolonged reactivity in snowpack tests.

Regions covered