Avalanche forecast

Lizard-Flathead

Feb 15, 2019Avalanche Canada
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Archived · expired 8 years ago

Avalanche danger

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

A storm is incoming, but total snowfall amounts for Thursday night into Friday are uncertain. The forecast herein assumes 30+ cm of snow accumulation by Friday afternoon.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3.5
    All this recent storm snow is rapidly loading a weak layer of surface hoar or a crust. The surface hoar is likely best preserved in shaded and sheltered areas between 1600 m and 1900 m. The crust exists on southerly aspects at all elevations.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–2.5
    More snow is forecast, but there is uncertainty in amounts. It could be 10 cm or could be 30+ cm. This snow could form large avalanches and step down to deeper weak layers. Avoiding avalanche terrain is the prudent choice.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

THURSDAY NIGHT: Cloudy with snowfall, accumulation 15 to 30 cm, alpine temperature -10 C.FRIDAY: Cloudy with snowfall, accumulation 5 to 15 cm, moderate to strong southwest wind, alpine temperature -8 C.SATURDAY: Cloudy with snowfall, accumulation 10 to 20 cm, light to moderate southwest wind, alpine temperature -13 C.SUNDAY: Mostly cloudy with light snowfall, accumulation 5 cm, light north wind, alpine temperature -20 C.

Avalanche Summary

There was a natural avalanche cycle that occurred on Wednesday, with many large (size 2 to 3) storm slab avalanches observed. The avalanches were generally 20 to 40 cm deep, on northerly aspects, and within all elevation bands.

Snowpack Summary

More snowfall is expected Thursday night into Friday, with total amounts uncertain but could be upwards of 20 cm or more. This new snow will overly around 30 to 50 cm of recent snow, which sits on variable layers, including wind-affected snow at treeline and alpine elevations, feathery surface hoar crystals in shaded and sheltered areas below treeline, and a melt-freeze crust below 1600 m.The mid-January layer of surface hoar or a crust is buried around 70 cm. The surface hoar is found on shaded and sheltered slopes and is most prominent between 1600 m and 1900 m. The melt-freeze crust is found on south aspects at all elevations.The remainder of the snowpack is generally well-settled. Thin snowpack areas, such as in the east of the region, may find weak and sugary faceted grains near the base of the snowpack.

Regions covered