Avalanche forecast

Coquihalla

Mar 9 – 10, 2023Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Lingering wind slabs may remain reactive to human triggers on a variety of aspects in the alpine.

Avoid travelling on slopes below cornices.

Avalanche problems

  • Wind Slabs

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

    Lingering wind slabs may remain reactive on a variety of aspects in the alpine.

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    1.5–3

    Cornices are large and may fail with daytime heating. Cornice failures act as heavy triggers and can trigger large avalanches on slopes that a single rider would not trigger.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–3

    There are several crusts in the mid/lower snowpack. Their depth ranges from 150-200 + cm.

    A large trigger, such as a cornice fall or smaller avalanche in motion, could trigger a very large avalanche on one of these deeply buried weak layers. A single rider is unlikely to trigger this layer unless they are in a steep, rocky, and shallow snowpack area.

Confidence

Moderate

Avalanche Summary

Naturally triggered size 1 wet loose avalanches were reported on steep sunny aspects on Tuesday.

On Saturday, explosive avalanche control work resulted in numerous very large(size 3-4) persistent slab avalanches. They occurred on a variety of aspects below steep, wind loaded treeline ridgetops and large alpine features.

Snowpack Summary

Cornices are large and may fail with daytime heating.

Sun crust on sunny aspects. Recent southeasterly winds formed wind slabs on a variety of aspects at treeline and above. These slabs are sitting on either hard surfaces or small facets.

There are several crusts in the mid/lower snowpack. Their depth ranges from 150-200 + cm.

A large trigger, such as a cornice fall or smaller avalanche in motion, could trigger a very large avalanche on one of these deeply buried weak layers. A single rider is unlikely to trigger this layer unless they are in a steep, rocky, and shallow snowpack area.

Weather Summary

Wednesday Night

Clear skies / Light southeast ridgetop wind / Low temperature at treeline -11 C / Freezing level valley bottom.

Thursday

Mix of sun and cloud / Light southeast ridgetop wind / High temperature at treeline -3 C / Freezing level 1100 m.

Friday

Cloudy with isolated flurries; 0-3 cm / Moderate southeast ridgetop wind / High temperature at treeline -4 C / Freezing level 900 m.

Saturday

Mix of sun and cloud / Light southwest ridgetop wind / High temperature at treeline -2 C / Freezing level 1100 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.
  • Avoid exposure to slopes that have cornices overhead.
  • Be alert to conditions that change with elevation and sun exposure.

Regions covered