Avalanche forecast

Purcells

Mar 18 – 19, 2024Avalanche Canada
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Avalanche danger

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

Very large persistent slab avalanches remain likely to human trigger, especially at treeline and above.

Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2–4

    A crust with weak facets overtop is down 40 to 110 cm. Very large human triggered avalanches occurring on this layer are likely on Tuesday, especially at treeline and above.

  • Loose Wet

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

    If triggered loose wet avalanches may step down to deeper layers, resulting in very large avalanches.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–4

    A widespread weak layer exists at the bottom of the snowpack. Large triggers, such as falling cornices or smaller avalanches in motion may have the potential to trigger this deeply buried weak layer.

Confidence

Moderate

Avalanche Summary

Numerous naturally triggered persistent slab and deep persistent slab avalanches up to size 3.5 (very large) were reported on all aspects and elevations on Sunday.

Snowpack Summary

A weak surface crust forming overnight will break down quickly throughout the day.

A widespread, hard crust down 40 - 110 cm with weak facets above continues to be the primary layer of concern for natural and human triggering of very large persistent slab avalanches.

Cornices have become large and looming, and are more likely to fail during periods of warming.

The bottom of the snowpack is generally weak and faceted, with the potential to produce very large avalanches. The most likely areas to trigger this deeply buried weak layer are steep, rocky areas in the alpine with a shallow or thin to thick snowpack.

Weather Summary

Monday Night

Clear skies. 10 to 20 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1000 m.

Tuesday

Mix of sun and cloud. 10 to 20 km/h southwest ridgetop wind. Treeline temperature 3 °C. Freezing level 2400 m.

Wednesday

Mix of sun and cloud with isolated flurries, 0 to 3 cm of snow (above 1700 m). 10 to 20 km/h west ridgetop wind. Treeline temperature -1 °C. Freezing level 2000 m.

Thursday

Mix of sun and cloud with isolated flurries, 3 to 5 cm of snow (above 1400m). 10 to 20 km/h west ridgetop wind. Treeline temperature -3 °C. Freezing level 1700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Keep in mind that human triggering potential persists as natural avalanching tapers off.
  • Be aware of the potential for large, deep avalanches to run full path or even longer.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
  • Cornice failure may trigger large avalanches.

Regions covered