Lawinenlagebericht

Lizard-Flathead

Apr 13 – 14, 2019Avalanche Canada
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Archiviert · abgelaufen 7 years ago

Lawinengefahr

Mon
Tue
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering

Kernpunkte

If we wake up to more than 20 cm of storm snow, then these danger ratings should all be bumped up one level, so moderate becomes considerable. New snow and wind Saturday night may produce a natural avalanche cycle if the "Fernie Factor" kicks in...

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible - Likely
    Größe
    1–2
    Watch for fresh slab development, especially in high elevation north facing features where human triggering is most likely near ridgecrest. High elevation south and west slopes could produce heavy sluffing as the new snow slides on a crust.
  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible - Likely
    Größe
    1–2
    Sunny periods Sunday combined with fresh storm snow will likely initiate loose wet avalanche activity. The likelihood of loose avalanches increases as temperatures warm throughout the day and/or if the sun comes out for an extended period of time.

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain on Saturday

Weather Forecast

A frontal system should track into the region late Saturday into Saturday night. We're expecting it to be quite convective which makes it hard to pin down total snow amounts, but right now it sounds like the storm could produce up to 10 cm before dark, and another 8 to 15 cm Saturday night, possibly more if the notorious Fernie Factor kicks in.SATURDAY NIGHT: Freezing level around 1500 m, moderate to strong southwest wind, 8 to 15 cm of snow.SUNDAY: Scattered cloud cover initially building to broken cloud cover in the afternoon, freezing level around 1600 m, moderate to strong west/southwest wind, 4 to 8 cm of snow possible. MONDAY: Scattered cloud cover, freezing level rising to around 1700 m, light variable wind, trace of snow possible. TUESDAY: Scattered cloud cover clearing to just a few clouds around lunch, freezing level rising to around 2000 m, light variable wind, no significant snowfall expected.

Avalanche Summary

On Friday small loose wet natural avalanches were reported from steep south facing terrain.On Thursday, explosive control was able to initiate a few loose dry avalanches up to size 1.5 which failed in the recent storm snow. In the afternoon skier controlled loose wet avalanches were easily triggered at treeline and below up to size 1.5 on sunny aspects. No natural avalanche activity was reported and no new avalanches were noted in alpine elevations.

Snowpack Summary

15 cm Thursday night brings 20-35 cm of recent accumulated snow since last weekend which sits above a supportive crust at treeline and in the alpine. During the heat of the day, especially under direct sun, the snow surface becomes moist or wet almost everywhere. The exception being high elevation north facing features. Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where isolated reactive wind slabs may exist and a well settled slab rests on weak facets (sugary snow). Although unlikely, human triggering of persistent slabs on this layer may still be possible, especially in rocky alpine terrain with a shallow or highly variable depth snowpack. Below treeline the snowpack is becoming isothermal.

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