Avalanche forecast

South Rockies

Apr 14 – 15, 2021Avalanche Canada
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Avalanche danger

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

As freezing levels rise, the likelihood for large cornice failures and wet loose avalanches will increase. Start early and plan to be off large slopes before the heat of the day. 

Check out the latest Forecaster's Blog for more information on managing current conditions. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1–2

    Watch for pockets of unstable snow in steep alpine terrain.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Strong solar radiation and warming may trigger the large cornices that hang over ridgelines.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2.5

    Expect natural wet loose avalanches to occur on solar aspects when the sun comes out.

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

  

WEDNESDAY NIGHT: Clear / Moderate, northeast ridgetop wind / alpine low temperature -5 / Freezing level 1500 m.

THURSDAY: Sunny / Light, northeast ridgetop wind / alpine high temperature 5 / Freezing level 2400 m.

FRIDAY: Sunny / Light, northeast ridgetop wind / alpine high temperature 7 / Freezing level 2500 m.

SATURDAY: Sunny / Light, northwest ridgetop wind / alpine high temperature 9 / Freezing level 2700 m.

Avalanche Summary

Recent reports are limited to a few small dry loose and wet loose avalanches on Sunday and Monday. Warm sunny weather this week will increase the size and likelihood of wet loose avalanches and cornice falls.   

Prolonged warming may increase the sensitivity of deeply buried layers later this week, although there is a fair bit of uncertainty about how likely this is in the South Rockies region. There have been some notable slab avalanches reported to the north of the region over the last few days including a skier triggered avalanche in Kananaskis Country on Saturday (see reports here and here) as well as a natural deep slab avalanche in Kootenay National Park on Tuesday (see photo here). These avalanches provide a good reminder of why it's good to be extra cautious during the heat of the day this time of year.

Snowpack Summary

North alpine terrain has roughly 30 cm of settling powder with wind slabs possible on steep exposed slopes. Other terrain is undergoing a melt-freeze cycle with successive days of warm sunny weather. The lower snowpack is generally strong and settled, however weak snow at the base of the snowpack may become a concern when things really warm up in the coming days. The snow line is creeping up to higher elevations, so some common access points are now snow free.

Terrain and Travel

  • Extra caution is needed around cornices under the current conditions.
  • Avoid exposure to slopes that have cornices overhead.
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Carefully evaluate steep lines for wind slabs.

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