Avalanche forecast

North Rockies

Feb 6 – 7, 2022Avalanche Canada
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Avalanche danger

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

Rising temperatures will keep the likelihood for humans to trigger avalanches increased, particularly where recent snow loaded a buried weak layer. 

Avalanche problems

  • Storm Slabs

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

    The recent storm brought around 40 to 60 cm of snow. Wind slabs will be found in lee terrain features at higher elevations from strong southwest wind. Storm slabs are found in sheltered terrain. The forecast warm temperatures will further promote slab development. These slabs will be particularly touchy where they are loading a weak layer of surface hoar crystals, which is most likely found in openings at and below treeline. Large, wide-propagating avalanches could result where this layer is present. 

    The presence of this buried weak layer was reported from the Torpy Sande and Pine Pass areas up to treeline and can be expected up to treeline in the northern part of the region.

  • Loose Wet

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

    Warm temperatures and sun in the afternoon will increase the likelihood of wet loose avalanches. Be especially cautious on and below slopes that are exposed to the sun.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

SATURDAY NIGHT: Mostly cloudy, up to 5 cm new snow, strong southwest wind, alpine temperature -3 C, freezing level 1400 m. 

SUNDAY: Mix of sun and cloud with intermittent snowfall, up to 5 cm new snow, moderate to strong southwest wind, alpine temperature 0 C, freezing level 1800 m.

MONDAY: Cloudy with snowfall, accumulation 20 to 30 cm, strong southwest wind, alpine temperature -1 C, freezing level 1500 m.

TUESDAY: Cloudy, 5 to 10 cm new snow, moderate to strong southwest wind, alpine temperature -3 C, freezing level 1500 m.

Avalanche Summary

On Friday a natural avalanche cycle was reported with small storm slab avalanches up to size 1.5. Most avalanches were observed at and below treeline. A couple large (size 2) slab avalanches were reported at treeline on a southwest and an east aspect. Observations on Friday were limited due to visibility.

Large avalanches are expected in areas where the buried surface hoar described in the Snowpack Summary exists. 

Looking towards Sunday, avoidance of consequential avalanche terrain is your best bet for having a safe day. Storm and wind slabs will be very touchy due to all the recent snow and wind. The snow will need time to stabilize.

Snowpack Summary

The recent storm brought 40 to 60 cm for much of the region, with the most in the southwest of the region and the least to the east of the divide and in the north. The snow has likely formed storm slabs in sheltered areas and wind slabs in lee terrain features from strong southwest wind. These slabs will remain touchy for the remainder of the weekend as the freezing level rises and the air gets warmer.

The snow will be particularly touchy where it sits on a weak layer of surface hoar crystals. Reports suggest that the surface hoar is likely most prominent in sheltered openings at and below treeline but could extend into wind-sheltered terrain in the alpine. Example terrain features to treat as suspect include the lee side of protected ridges, openings in the trees, cut blocks, and burns.

The lower snowpack is generally strong and well-bonded. The base of the snowpack is expected to be weak and faceted in shallow, rocky slopes east of the divide.

Terrain and Travel

  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Avoid steep slopes when air temperatures are warm, or solar radiation is strong.

Regions covered