Lawinenlagebericht

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
1 · Gering
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 5 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

A generally stable snowpack may be topped with small new wind slabs at isolated above treeline locations by this afternoon. These wind slabs may build as westerly wind transports the 3-5” inches of new snow forecast to fall today. Most of our terrain will lack this new avalanche problem, instead offering a dusting of new snow on the widespread rain crusts formed last week. You can easily identify any new wind slabs today by watching for areas where snow is drifting to more than a few inches of accumulation on top of the crust.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    1

    You’ll be hard pressed to find an avalanche problem in most of our terrain today, but small new wind slabs may develop through the day, particularly in above treeline areas that are exposed to the wind. Light west winds with some stronger gusts will affect the few inches of new snow that should accumulate. Our widespread surface crusts have capped any existing snow available for wind transport, so the light wind will only have today’s snowfall to work with. The surface crust would provide a smooth bed surface for avalanches if wind slabs do develop. Watch for wind deposited drifts of snow that are thicker than the otherwise thin coat of new snow we’re receiving today to identify this wind slab avalanche problem.

Avalanche Discussion

New snow followed by warming and rain last week resulted in a surface crust capping a snowpack that’s become stable. Some surface hoar was buried intact early last week in the Kootenai and Selkirks & Cabinets forecast zones, but we think a little more rain and a little less snow melted surface hoar rather than bury it in the St. Regis & Silver Valley zone. It looks like the St. Regis & Silver Valley zone will receive the most snow today and might start to have some fun, softer, though still dust on crust riding conditions as the 3-5” of snow accumulates.

The surface crusts, thick and robust at low elevations and thin and subtle at high elevations, are worth remembering as our season progresses. Crusts provide a smooth bed surface for future avalanches. Crusts can also be problematic because weak, faceted snow grains tend to develop over time near crusts, especially around thin crusts that are near the snowpack surface. We haven’t observed faceting near the crusts yet. Without snow forecast to deeply bury the crust any time soon, we’ll be watching for the potential development of these faceted weak layers as future avalanche problems. Please submit an observation if you find sugary, faceted snow near the crusts or anything else of interest, these observations help all of us!

Friends of IPAC has a bunch of avalanche and safety courses coming up, find more information and view the schedule here. There’s something for everyone, from excellent Level 1 Refresher courses to a Level 2 and also Wilderness First Aid that’s tailored to winter backcountry users. It’s a great time to think about taking one of these fun classes that can help you be safer in mountains!

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