Avalanche forecast

Kootenay Boundary

Mar 19 – 20, 2019Avalanche Canada
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Avalanche danger

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

Travel in avalanche terrain is not recommended. Larger avalanches from above may run to valley bottoms, especially from sun exposed slopes.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1.5–3
    Warm temperatures are penetrating deeper into the snowpack and a cohesive slab now sits above a series of weak layers. Its hard to say how long it will take for this warming to wake up the more deeply buried weak layers.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely - Very Likely
    Size
    1–2
    Loose wet activity is expected to continue on all aspects and elevations. Cornices are softening up and becoming weak. You don't want to be under or near one of these looming monsters when they fail.

Confidence

Moderate -

Weather Forecast

Warm temperatures persist through the forecast period. WEDNESDAY: A mix of sun and cloud with alpine temperatures holding at + 8 degrees. Ridgetop winds light from the southeast and freezing levels 3300 m. THURSDAY: A mix of sun and cloud Alpine temperatures +7 degrees with freezing levels 3200 m. Ridgetop winds light from the southeast. FRIDAY: Cloudy with some sunny periods. Alpine temperatures near +8 degrees and freezing levels dropping to 3000 m. Ridgetop winds light from the East.

Avalanche Summary

On Monday, natural loose wet avalanches up to size 2 were reported from the region. These avalanches failed on all solar aspects (East through West) between 1600 to 2300 m. Some larger wet slab avalanches up to size 3 were also reported and triggered by explosives on southeast to southwest aspects between 1900-2200 m. Continued warming and a lack of overnight re-freeze we expect to see natural avalanche activity to continue on all aspects and elevations.

Snowpack Summary

Currently, solar aspects are showing signs of melt by day and a freeze by night. In some locations, sheltered northerly aspects have new surface hoar forming and variable wind effect remains on exposed slopes at treeline and in the alpine. The current snowpack is complex and with the continued warming and little overnight re-freeze the snowpack will continue to break down. The bigger questions are deeper in the snowpack. Two crusts exist in the upper snowpack and the bond of the overlying snow is most concerning with deteriorating. The first crust is down 20 to 30 cm and loose wet avalanches have slid on this interface. The deeper one down 60-95 cm has also been producing easy shears in test profiles and potentially just waiting for enough heat to penetrate and deteriorate before avalanches start failing on it, if they do? Its hard to say how many hot days and warm nights it will it take to wake up the more deeply buried weak layers.

Regions covered