Avalanche forecast

Northwest Coastal

Feb 21 – 22, 2023Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Avoid wind-loaded areas. Fresh reactive wind slabs are expected to form throughout the day as northeasterly winds redistribute yesterday's storm snow.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1.5–3

    Northeasterly winds will redistribute 30-50 cm of recent new snow into fresh, reactive wind slabs. These slabs will form in a reverse loading pattern and at lower elevations than you might typically expect. Wind slabs may be particularly reactive where they overlie a crust.

Confidence

Moderate

Avalanche Summary

Stormy weather has limited observations in the past few days, but evidence of a natural storm and wind slab cycle has been observed throughout the region. One notable skier accidental size 2 storm slab occurred in the Shames backcountry on Sunday. See details in the MIN report.

Looking forward to Tuesday, we expect fresh, reactive wind slabs to form in a reverse loading pattern and at lower elevations than you might typically expect. These wind slabs may be particularly reactive where they overlie a crust.

Snowpack Summary

Up to 40 cm of new snow has accumulated in the past 2 days. Northeasterly winds are expected to redistribute this new snow into fresh, reactive wind slabs. This new snow overlies last week's 60cm of storm snow and wind-affected surfaces in exposed areas.

Up to 80cm now sits over a layer of small surface hoar, facets and wind-affected surfaces. Below treeline, a new crust could exist up to 1000m.

A layer of facets and a crust from late January can be found down 100 to 200cm. Below this layer, the snowpack is generally well-settled and right-side up.

Weather Summary

Monday night

Cloudy with clear periods and flurries, trace to 10 cm of accumulation. Alpine temperatures drop to a low of -8 °C. Ridge wind northeast 25-50 km/h. Freezing level at valley bottom.

Tuesday

A mix of sun and cloud. Alpine temperatures reach a high of -9 °C. Ridge wind northeast 25 km/h gusting to 50 km/h. Freezing level at valley bottom.

Wednesday

Sunny. Alpine temperatures reach high of -14 °C. Ridge wind northeast 25 km/h gusting to 60 km/h. Freezing level at valley bottom.

Thursday

Sunny with cloudy periods. Alpine temperatures reach a high of -16 °C. Ridge wind east 25 km/h gusting to 50 km/h. Freezing level at valley bottom.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Keep your guard up at lower elevations. Wind slab formation has been extensive.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.

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