Avalanche forecast

Lizard-Flathead

Mar 11 – 12, 2018Avalanche Canada
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Archived · expired 9 years ago

Avalanche danger

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

Freezing levels well above the mountain tops and sunny skies are intensely warming the snowpack, particularly around midday. Best to avoid areas with sun exposure, wind effect, and overhead avalanche terrain. Read our blog on the impact of warming.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Wind slabs exist in the region and may still be reactive to human triggers. Use caution when entering into lee features.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Rising freezing levels and sunny skies are causing intense warming of the snowpack on solar aspects. Peak danger will likely be during afternoon hours.  Pay close attention to the effects of the sun on avalanche terrain and avoid overhead exposure.

Snowpack Summary

20-30 cm of recent storm snow is settling rapidly with warm daytime temperatures. Expect moist snow on solar aspects and on all aspects up to 1400 m. This new snow is sitting on patchy surface hoar in parts of the region.Cornices are large and prone to failure with warm air temperatures and sunny skies.In the upper to mid snowpack, a surface hoar or facet layer buried mid-February is now 80 to 110 cm below the surface on sheltered northerly aspects.Deeper in the snowpack, the widespread mid-December and late November weak layers are composed of a combination of crusts and sugary facets which are down 200-300 cm. These layers have been dormant but may be awoken by the warm and sunny weather throughout the weekend or by a large trigger, such as a falling cornice.

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

MONDAY: Sunny, light southwesterly winds, alpine temperature 1 C, freezing level 2300 m.TUESDAY: Sunny, light southwesterly winds, alpine temperature 3 C, freezing level 2600 m.WEDNESDAY: Mostly sunny, light southwesterly winds, alpine temperature 3 C, freezing level 2500 m.

Avalanche Summary

Numerous storm and wind slabs to size 2 were reported in the region, being triggered naturally and by explosives. They were on all aspects, 30 to 50 cm deep, and most often at alpine elevations. Small loose avalanches were also noted on solar aspects.The forecast warming and sunshine may wake up a deeper weak layer on steep south facing slopes resulting in large and destructive avalanches.

Regions covered