Avalanche forecast

Northwest Inland

Mar 14 – 15, 2021Avalanche Canada
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Avalanche danger

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

With 20 cm of storm snow the main concern is reactive wind slabs in the alpine. The exception is the southwest of the region with up to 100 cm of new snow which might need more time to stabilize. Be cautious and watch for signs of instability.

Avalanche problems

  • Storm Slabs

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

    Most of the region received around 20 cm new snow during the recent storm except for the southwest of the region where new snow amounts range between 50 and 100 cm. Storm slabs will remain reactive to human traffic, especially where it sits on surface hoar on northerly aspects and in sheltered terrain features around treeline or a melt-freeze crust on southerly aspects and below treeline.

    Moderate westerly wind and strong southwest wind redistributed the new snow and developed reactive wind slabs in lee terrain features in the alpine and at treeline. The strong wind may have formed wind slabs lower down on slopes than expected. 

    The wind contributed to cornice growth and the additional load may lead to cornice failures.

Confidence

Moderate - Recent weather patterns have resulted in a high degree of snowpack variability within the region.

Weather Forecast

SUNDAY NIGHT: Cloudy and clearing towards early morning, trace of new snow, 40 km/h northwest wind, alpine low -17 C.

MONDAY: Sunny and increasing cloud in the afternoon, trace of new snow, 30 km/h southwest wind, alpine high -8 C.

TUESDAY: Cloudy, 5 to 10 cm new snow, 40 km/h southerly wind, alpine high -1 C, freezing level rising to 1000 m.

WEDNESDAY: Mix of sun and cloud, 5 to 10 cm new snow, 40 km/h southerly wind, alpine high 0 C, freezing level 1000 m.

Avalanche Summary

A natural avalanche cycle with storm slab avalanches up to size 2 and small wet loose avalanches were reported on Saturday in the southwest of the region. Explosives triggered wet slab avalanches up to size 2.5. A few small natural wind slabs on steep northeast facing alpine features and several small wet loose avalanches at all elevations were observed as well. 

Several small natural wet loose avalanches of size 1 and a few small skier triggered wind slab avalanches (size 1) were reported on Friday.

Snowpack Summary

Most of the region received around 20 cm new snow during the recent storm except for the southwest of the region where snow amounts range between 50 and 100 cm. The snow fell with strong southerly wind. At lower elevations the precipitation fell as rain. The new snow may overly widespread wind affect at alpine elevations, feathery surface hoar on northerly aspects and in sheltered terrain features around treeline, or a melt-freeze crust on southerly aspects and below treeline.

There are presently no widespread deeper concerns. However, faceted snow at the base of the snowpack exists in much of the region and always has the potential of being triggered in shallow, rocky slopes.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Regions covered