Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Strong winds and fresh snow have continued to build wind slabs on the leeward side of ridges in terrain exposed to the wind. You can avoid triggering and avalanche today by steering clear of terrain steeper than 35 degrees that has been loaded by recent south and southwest winds. Steep chutes and terrain directly below ridgelines at upper elevations will be the most likely areas to trigger and avalanche today. The safest conditions and excellent riding can be found below treeline today.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Two human triggered avalanches were reported yesterday in the Silver Valley in wind loaded terrain.

    https://www.idahopanhandleavalanche.org/observations#/view

    Recent winds and another 5-7" of new snow have continue to load NW-N-E facing slopes in the upper and mid elevations. To avoid these problem areas, look for recent drifts,  cornices, and hardness changes in the snowpack surface.  Avoid slopes steeper than 35 degrees near and above treeline that have been loaded. Terrain directly below ridgeline and steep chutes will be possible locations to trigger a wind slab avalanche today.

    Wind transported snow.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2.5

    The weather over past two weeks has added complexity to the upper snowpack. Various interfaces exist both above and below the ice lens, formed on February 19th, 1-2 feef below the surface. The Luck Friday Crust from January is now buried 2-4 feet deep. While we have not seen recent propagation, I am still skeptical of triggering a slide on these low likelihood, high consequence layers. I would definitely evaluate carefully before committing to steep terrain with consequential runouts, especially where the snowpack is shallow and near trigger points like rock bands and protruding rocks or trees.

    (3/2/2023)

    Buried graupel, Feb 19 ice lense, and various interfaces buried 50cm from surface.

Avalanche Discussion

Wind loading took place throughout the day Thursday as we toured around Goose Peak. It was puking snow sideways all day with wind howling out of the south-southwest. Strong winds, with gusts into the 40’s, transported available snow onto the lee side of ridges and gullies. Our parked snowmachines were partially buried by wind swept snow in just a few hours. We observed cracking in drifted snow and density changes become more prevalent throughout the day.

The upper snowpack has gained complexity in the past couple weeks. Yesterday we found the February 19th rain crust buried as a blue ice lens 30 to 50 centimeters below the surface at various elevations and aspects. A few centimeters above the ice lens we found a layer of well-preserved graupel, as well as various interfaces buried deeper in the snowpack. While our pit tests did not show propagation, I maintain a healthy dose of suspicion of these layers and will keep an eye on them in the weeks to come.

Overall skiing and riding conditions are decent in wind sheltered terrain. My biggest concern today is touchy wind slabs on our zone's biggest terrain, like Steven's Peak, where consequences of being taken for a ride are severe. Other than that, if the wind abates and the sun pokes out skiing and riding should be pretty fun. Arctic air will enter the arear Saturday evening and cause the winds to become more easterly, along with a drop in temperatures. 

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