Avalanche forecast

South Coast Inland

Apr 18 – 19, 2021Avalanche Canada
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Avalanche danger

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

Start (and finish) your day early to avoid exposure to sun-exposed avalanche terrain. Steer clear of cornices overhead and plan your egress route carefully.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3

    Cornices are at their largest at this time of year, and become weaker with warm temperatures and solar radiation.

  • Wet Slabs

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

    The likelihood of wet slab avalanches increases during prolonged periods of warm temperatures, as the heat penetrates deeper into the snowpack. In the neighboring Seat to sky Region multiple very large wet slab avalanches have been observed in the last couple days. These avalanches are dense, destructive and can run far, reaching otherwise snow-free valley bottoms.

    Wet loose avalanche activity can also be expected on sun exposed slopes and below treeline. These avalanches are generally smaller than wet slabs but they can gather mass as they travel and reach low elevations.

Confidence

Moderate - Confidence is due to a stable weather pattern; little change is expected for several days. Uncertainty is due to the limited number of field observations.

Weather Forecast

Sunday night - Clear / strong northeast wind / alpine low temperature near -2 / freezing level falling to 1200 m

Monday - Sunny / light wind / alpine high temperature near +1 / freezing level 2400 m

Tuesday - Sunny / light wind / alpine high temperature near +1 / freezing level 2400 m

Wednesday - Sunny / light wind / alpine high temperature near +2 / freezing level 2500 m

Avalanche Summary

The few reports still trickling in confirm that widespread loose wet and cornice activity was still ongoing as of the weekend. The Coquihalla zone has also seen glide slabs up to size 3.

In neighboring Sea to Sky region, multiple wet slab avalanches were observed over the weekend near Whistler, size 2-4. Many of these involved the full depth of the snowpack, running to valley bottom. We suspect similar activity to have occurred in the Inland region as well.

Snowpack Summary

Radiant cooling and (finally) a slight dip in freezing levels overnight have likely formed a crust in many areas. It should quickly soften during they day with sunshine and warm temperatures. Steep north aspects at the highest elevations may still hold dry snow.

Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, especially when temperatures remain above zero overnight.

Terrain and Travel

  • Avalanche hazard is expected to to increase througout the day, think carefully about your egress.
  • Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Keep in mind that wet avalanches can be destructive due to their high density.
  • Avoid lingering or regrouping in runout zones.

Regions covered