Avalanche forecast

South Rockies

Feb 16, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

Sun
Mon
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Highlights

Total snowfall amounts for Friday night into Saturday are uncertain. The forecast herein assumes 30+ cm of snow accumulation. New snowfall will likely be reactive to both natural and human activity and it is also loading buried weak layers.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1.5–3
    A weak layer of surface hoar is buried around 50 to 80 cm, which is best preserved in shaded and sheltered areas between 1600 m and 1900 m. The likelihood of triggering this layer will increase with further snowfall.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2.5
    More snow is forecast Friday night, but there is uncertainty in the amounts. It could be 10 cm or 30+ cm. Avoiding avalanche terrain is the prudent choice. This snow could form large avalanches and step down to deeper weak layers.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

FRIDAY NIGHT: Cloudy with snowfall, accumulation 10 to 20 cm, light to moderate west wind, alpine temperature -10 C.SATURDAY: Cloudy with snowfall, accumulation 5 to 15 cm, light to moderate west wind, alpine temperature -15 C.SUNDAY: Mostly cloudy with light snowfall, accumulation 5 cm, light northeast wind, alpine temperature -23 C.MONDAY: Mostly clear skies, light north wind, alpine temperature -18 C.

Avalanche Summary

On Thursday, there was further evidence of the widespread natural avalanche cycle that occurred in the region during Wednesday's storm. The avalanches were generally within the recent storm snow, around 30 to 60 cm deep, and at treeline and alpine elevations.

Snowpack Summary

More snowfall is expected Friday night into Saturday, with total amounts uncertain but could be upwards of 25 cm or more. The snow may have slab properties where it falls with wind and could be low-density and loose in sheltered areas. This new snow will overly around 30 to 50 cm of recent snowfall, which sits on wind-affected snow in exposed areas and a melt-freeze crust below 1700 m. All this recent snowfall is likely to be reactive to human traffic.The mid-January layer of surface hoar is buried around 50 to 80 cm. The surface hoar is found on shaded and sheltered slopes and is most prominent between 1600 m and 1900 m but has been found up to 2200 m.The middle of the snowpack is generally consolidated. The bottom half of the snowpack is unconsolidated and composed of weak and sugary faceted grains.

Regions covered