Lawinenlagebericht

Lizard-Flathead

Mar 1 – 2, 2022Avalanche Canada
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Archiviert · abgelaufen 5 years ago

Lawinengefahr

Thu
Fri
Hochgebirge
4 · Gross
Waldgrenze
4 · Gross
Unterhalb
4 · Gross
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Kernpunkte

Still stormy!

Heavy rain and snow overnight will continue to keep avalanche danger elevated. Even as snowfall rates taper on Tuesday, the snowpack will need time to adjust to the new load. 

Travel in avalanche terrain is not recommended and stay clear of runout zones.

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    Storm avalanches have the potential to step down to this deeper persistent layer in sheltered north-facing treed terrain.

    Persistent slab avalanches are still possible due to a layer of buried surface hoar that is likely down around 70-80 cm. This problem is tricky to pin down because of its spotty distribution (it isn't a problem everywhere). It has been most reactive recently in the Flathead with reports of rider triggering (see MIN post), whumpfing and propagation in snowpack tests a week ago.

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Very Likely - Almost Certain
    Größe
    1–3.5

     Continued snowfall, southwest wind and high freezing levels will keep avalanche danger high on Tuesday. Avoiding avalanche terrain and staying clear of overhead hazard is the best way to stay safe during periods of heavy snow accumulation. As the snowpack becomes saturated with rain at lower elevations, storm slabs may entrain wet loose snow and run further than expected. 

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2.5

    Loose wet avalanches will be a concern at lower elevations where rain has destabilized the snowpack causing it to lose cohesion. These avalanches can start from a point and pick up a surprising amount of mass, especially in steep terrain and gully-type features. Storm slabs may entrain wet loose snow at lower elevations and run further than expected. Steer clear of steep terrain and don't walk the dog in runout zones!

Confidence

High - We are confident the likelihood of avalanche will increase with the arrival of the forecast weather.

Weather Forecast

Monday night: Ongoing heavy precipitation with 20-40 mm, moderate southwest wind, freezing levels rising to 1900-2000 m and treeline temps hovering around zero.

Tuesday: Precipitation continues with 10-20 mm, moderate to strong southwest wind, freezing levels hovering around 1900-2000 m and treeline temperatures around 2 degrees. 

Wednesday: Flurries possible 5-10 cm, light to moderate southwest wind, some overnight recovery is possible, but freezing could still rise to about 1700 m during the day.

Thursday: Overcast with flurries, light southwest wind. Good overnight recovery but freezing levels rising during the day.

Avalanche Summary

Visibility was poor but numerous size 2 avalanches were reported from operators in the Lizard Range on Monday.

Snowpack Summary

By Tuesday morning there could be over 60-70 cm (depending on your location in the region) of new snow forming slabs over a variety of old surfaces like old wind affected snow, sun crusts, and cold weak crystals on shaded aspects. Rain will likely soak new snow overnight on Monday night at treeline and below treeline elevations.

Storm slabs or loose wet avalanches may step down to old persistent layers such as the surface hoar layer buried at the end of January. The distribution of this layer is spotty in nature but has produced avalanches and snowpack test results in the past week, mostly in the Flathead. While it does not appear to be as widespread or reactive in the Lizard Range, it has been found in some locations. 

The lower snowpack is well consolidated, with a crust/facet layer from early-December found near the bottom of the snowpack. It is currently considered dormant but with big rain on snow events, operators will be on guard. Check out the forecaster blog for more information. 

Terrain and Travel

  • Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

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