Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Last nights mild temperatures failed to refreeze the upper snowpack in many places. Wet loose avalanches will become likely on steep southern aspects as temps and solar radiation increase throughout the day. On Friday watch for signs of increasing instability, roller balls and deep ski penetration. Move to shaded north aspects by afternoon or head back to the rig. The deep persistent weak layers are still down there and widespread. Shallow trigger points or wet slides that step down could cut loose a large destructive avalanche. Continue to choose low angle slopes and simple terrain. By Saturday cool temperatures and cloud cover will decrease the hazard rating.

Avalanche problems

  • Loose Wet

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

    Warm weather and solar radiation have weaken the bonds in the near surface snowpack making point-release wet loose avalanches likely on steep southern aspects.  These in turn could step down to trigger wet slabs or the deep persistent slab.  If you start to punch through or see roller balls, head to shadier north aspect slopes or hang'em up for the day.

    If you see fresh roller balls head to shady north aspects or head home.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    The deep persistent weak layer is still out there intact and widespread. Activating a shallow trigger point could release a large destructive avalanche. I wouldn't feel comfortable stepping out into big avalanchable terrain yet. Stick to sub 30 degree slopes and simple terrain for now. Don't wake the dragon. 

    This is the debris field of a snowmobile triggered hard slab avalache just west of Dominion Peak that occured on Monday (HS-AM-R2-D2-I).

Avalanche Discussion

It might be time to breakout the zinc oxide and tear away pants! 

 We did not see propagation in our extended column tests, but we could easily identify crusts and weak layers buried deep down. Failure on these layers could release large destructive avalanches. I do not have enough confidence that the deep persistent weak layers can be sufficiently mitigated to convince me to step out into big high consequence terrain.  Shallow trigger points created by buried rocks and trees are still a concern and we have seen human caused avalanches on these layers in recent days. 

The warm weather and weak refreeze last night has weakened the upper snowpack on southern aspects. Ambient air temps in the 50's at 6,000 ft sure felt good on Thursday, but things started to get sloppy by early afternoon. On Friday plan to move to north aspects in the PM to avoid wet avalanche danger. On our way out I noticed a recent wet slide that went to ground in shallow snowpack, so caution is warranted at all elevations (see photo below). A return to cooler temps on Saturday will decrease the likelyhood of wet slides.

We are almost there, but patience and dicipline are still needed. Hang in there and stay vigilant.

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