Avalanche forecast

North Columbia

Feb 10 – 11, 2023Avalanche Canada
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Avalanche danger

Sun
Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Continue to make conservative terrain choices and consider the consequences of a chosen slope avalanching. Avoid shallow, rocky snowpack areas where triggering the deep persistent weak layer is still possible.

Be cautious around steep openings within and near treeline elevations as active loading continues.

Avalanche problems

  • Wind Slabs

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

    Make observations and asses conditions continually as you travel into different aspects and elevations. Southwest winds are redistributing storm snow into deep pockets at higher elevations. Slabs will likely be the deepest and most reactive on north and east aspects at treeline and above.

    Where direct sun is impacting snow surfaces watch for upper snowpack weakening and becoming more unstable. Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

    Keep in mind that wind slabs have the potential to step down to deeper weak layers, resulting in large and consequential avalanches.

  • Persistent Slabs

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

    Numerous problematic weak layers exist in the top meter of the snowpack. Recent large persistent slab avalanche observations are strong evidence that these layers are still an active concern in this region. These layers have been most prevalent in the southern part of the region.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2.5–4

    A layer of large and weak facets sits near the base of the snowpack. This layer continues to produce very large avalanches that can travel far. Riders are most likely to trigger an avalanche on this layer in steep, shallow terrain, or by triggering a smaller avalanche that could step down to this layer. Your best defence is to stay diligent in choosing low-consequence terrain away from overhead exposure. See more on the potential of triggering deeper weak layers in our latest Forecasters' Blog.

Confidence

Moderate

Avalanche Summary

With clearer weather on Wednesday, a widespread avalanche cycle from within the storm was observed across the region. Several persistent slab avalanches were reported between 2200 and 2400 meters on all aspects. Notable was a size 2 vehicle remote persistent slab avalanche, triggered from 70 m away on a northwest aspect. Several deep persistent slabs were reported to size 4 throughout the Selkirks and Purcells. Numerous wind slab and storm slab avalanches were reported to size 3 on all aspects at treeline and above.

On Tuesday, a few size 1 skier accidentals storm slab avalanches were reported 20-40 cm deep. Numerous natural avalanches were reported primarily on north and east aspects where storm snow and wind created deep pockets of slab. Explosive control produced numerous storm slab results to size 3.5.

On Monday, A skier accidental avalanche was observed in the Sun Peaks backcountry. The avalanche was a size 2 and is suspected to have run on a weak layer of surface hoar from late January. Several natural storm slab and wind slab avalanches were reported, size 1-2.5, on east and north aspects at treeline and alpine.

Snowpack Summary

Southwest winds have been redistributing storm snow into 20-30 cm soft slabs in exposed alpine and treeline areas. 40-90 cm of storm snow from the week sits above wind-affected surfaces and a crust that extends up to 1800 m in the northern part of the region and up to 2000 m further south. Small facets may be found above the crust.

Deeper in the snowpack two layers of surface hoar which formed in early January are 60 to 120 cm deep. These weak layers are still on our radar, although snowpack tests are indicating they may be strengthening.

Large and weak facets from November are near the base of the snowpack, which continue to produce very large avalanches in the region.

Weather Summary

Thursday Night

Partly cloudy clear periods and isolated flurries, trace accumulation. Southwesterly ridge wind 40-60 km/h. Alpine temperature low of -5 °C. Freezing level 500 m.

Friday

Cloudy with sunny periods and isolated flurries, 3-7 cm accumulation. Southwesterly ridge wind 40 km/h easing to 20 km/h in the afternoon. Alpine temperature high of -3 °C. Freezing level 1200 m.

Saturday

Cloudy with sunny periods and isolated flurries, trace accumulation. Westerley ridge wind 20 km/h. Alpine temperature high of -4 °C. Freezing level 1000 m.

Sunday

Cloudy with isolated flurries, 5-10 cm accumulation. Southwesterly ridge wind 40 km/h in the afternoon. Alpine temperature high of -2 °C. Freezing level 1200 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Minimize exposure to sun-exposed slopes when the solar radiation is strong.
  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.
  • Avoid shallow snowpack areas, rock outcroppings and steep convex terrain where triggering is most likely.

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