Lawinenlagebericht

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Lawinengefahr

Wed
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

At the highest elevations or where steep open slopes exist below 5,000 feet it is possible that you could trigger an avalanche.  The storm snow from last Thursday still reacts with moderate force applied in stability tests.  Deeper in the pack the sugary snow from the cold November combined with a buried layer of surface hoar gives me concern for big open slopes where anchoring from vegetation and rocks and such is low to nonexistent.

Lawinenprobleme

  • Storm Slabs

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

    Brian Hilland and I hit the Cabinet Mountains yesterday and ventured into the Trestle burn on Trestle Ridge.  Surface conditions were great with one foot of low density powder to slide on.  The places I have the most concern for this storm slab are where it will be wind effected.  On the south and east slopes we tested on the way up this layer was still light and fluffy; not real conducive to breaking as a slab.  The higher we got the stiffer the slab got.  Near the ridgeline and on multiple aspects due to shifting wind direction is where you might find this layer touchy enough to slide.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Brian and I threw the kitchen sink at the snowpack yesterday, using all of our tricks to see results in weak layers.  Only one compression test of three resulted in a break at the faceted snow near the base of the pack.  The buried layer of surface hoar above that was more stubborn, giving no results in compression tests, extended column tests, and rutschblock tests.  The picture shows the entire five feet of snowpack with the surface hoar and facet layers in the bottom third.  These results give me good confidence in many areas but the places to avoid are big open, steep, and unsupported slopes.  The ones you just want to tear into because they are untracked but caution is advised.  Ultimately, this is a weak snowpack structure due to the sugary crystals at the base of the pack and they are not supportive of a quickly added load.

Avalanche Discussion

It was very cold, in the high teens yesterday.  The wind near the ridgetop made it very cold indeed.  On our skis up to Trestle Ridge we found the surface snow light yet supportive due to a denser layer below.  Closer to the ridge we stopped since the snowpack got a little thinner and we experienced shallower pockets around rocks where we penetrated to the deeper sugary snow.  We chose not to venture into the mine field that existed higher up.  Up around Lunch Peak we found that surface hoar existed on many aspects above 5,000 feet.  This will get buried in our next round of snow this Thursday.  There is plenty of safe terrain to ride out there in the trees on lower angles.  It is still a little tough to get around due to fallen trees, obstacles, creek bottoms, and unburied alder so be careful.  It's going to continue to be cold so be prepared and realize that the cold will allow our avalanche problems to persist so keep that in your mindset.

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