Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Thu
Alpine
4 · High
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Very dangerous avalanche conditions will reemerge above 6,500 feet from another round of heavy rain and strong winds. The rain line will spike to around 8,000 feet on Wednesday and quickly overload buried weak snow layers. Wet snow hazards will remain at mid and lower elevations and travel below any steeper terrain is not recommended. 

Avalanche problems

  • Persistent Slabs

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

    Our persistent slab problem is very complex today, with multiple buried weak layers in the snowpack ranging from 2-3 feet deep. Heavy rainfall that climbed to at least 6500-7000 feet Monday night, percolated rapidly through our dry December snowpack, and provoked a natural avalanche cycle of large avalanches and at least a few very large events (size D3).

    Cooler temps yesterday offered a short reprieve, but today we will once again be hammered by an atmospheric river with unprecedented moisture and very high freezing levels for the month of December. Despite being tested once already, these weak layers have not had adequate time to heal. This was evident in stability tests on Monday, as well as at a crown profile investigation yesterday afternoon. Slopes above 7000 feet have not had their exam yet, and will be especially worrisome for today’s rain on snow event. 

    We recommend avoiding avalanche terrain all together during these remarkably warm and wet times. Very dangerous conditions exist on slopes steeper than 30 degrees.

    (12/9/2025) Photo: Jackson George

    A large slab avalanche observed on Jeru failed on a persistant weak layer of facets from early December.

  • Loose Wet

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

    Rain up to the higher elevations will weaken snow surfaces and make wet loose avalanches likely. Wet loose slides can be found in steep open slope areas today. These avalanches may start small but can gain mass and increase consequences. Due to the amount of new snow at mid and lower elevations recently, wet loose avalanches could quickly gain in size, and run far distances down slope as they entrain more snow. Seeing rollerballs that gain in size or sinking to your boot top in heavy, wet snow are red flags that this problem is materializing. Plan to avoid confined terrain features such as creek bottoms, large road cuts and above or below cliffs.

    (12/9/2025)

    Newly wetted snow at upper elevations will be susceptible to a cycle of wet loose avalanches as liquied water lubricates the snowpack on steep slopes for the frist time. At lower elevatiuons even relatively small wet loose avalanches can have dire consequences as debris piles up in gullies or entrained snow drags a rider over cliffs or through trees.

    Photo: Mikey Church

Avalanche Discussion

Rain on snow is starting to sound like a broken record. After a brief reprieve on Tuesday, the atmospheric river that dumped heavy snow and rain through Monday has moved back into our zones and will park itself over the Panhandle and NW Montana until it transitions out Friday. We are forecast to receive 1 to 4 inches of additional rain today into tomorrow. With temperatures climbing into the 40’s across our zones, the snowline will quickly rise to near, or exceeding, 8,000 feet today, wetting snow above 6,800 feet for the first time this week. The conditions are tricky out there right now. A widespread rain crust up to around 6,800 feet overlays a complex early season snowpack. At mid to lower elevations today’s warm rain may help break down the crust, allowing liquid water to percolate into the snowpack. While the introduction of moisture in the snowpack will help erase distinct layers over time, in the short term the introduced water will lubricate and further destabilize persistent weak layers.

 Yesterday, IPAC teams documented numerous persistent slab avalanches that had failed in the preceding days, including several large avalanches in the Selkirks. Results in pit tests demonstrated that the structure needed to sustain crack propagation still exists in the snowpack, and we can expect those conditions to be significantly more dangerous at elevations exceeding 6,500 feet where human triggered avalanches are likely. The flood of warm liquid all the way up the mountain means wet loose avalanches are possible at all elevations today.

 The forecast team did not issue a warning for the Silver Valley and Northern Bitterroot Zone this morning because we felt the conditions are sufficiently different from the northern zones to differentiate them. The overall shallower snowpack and lack of widespread continuity of persistent weak layers lower in the snowpack mean the avalanche problems are less pronounced, although still present in our mid elevation band. Considerable danger is challenging to navigate so if you venture out today don’t try to outsmart the problems. Conservative decisions today are the way to go.

 Weird weather breeds weird avalanche behavior. These near historic atmospheric river events have created conditions in the snowpack that none of us have witnessed in recent memory. How exactly the snowpack reacts to an additional 4 inches of rain is an open question, so please treat this period of elevated avalanche danger with respect and caution. 

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