Avalanche forecast

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Weird weather makes for unusual avalanche behavior. Dangerous slabs of snow around two feet thick are now being wetted by light to moderate rainfall. The added water weight is helping nudge numerous weak snow interfaces below closer to their tipping point. Wind-drifted slopes, in particular, will remain reactive and can produce the largest avalanches. Near the treeline and at lower elevations, wet snow hazards will grow in size and distribution as the dry snowpack gets more saturated. Travel with a conservative mindset by avoiding slopes over 30 degrees and those with steeper hazards directly above you.

Avalanche problems

  • Storm Slabs

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

    The official seasonal transition to spring arrived on March 20, and the mountains just received around two feet of snow since. This is the largest Snow Water Equivalent (SWE) load in portions of the Bitterroots and in the Silver Valley this season. This amounts to a broad brush 1.5 to 2.5 inches of SWE in the past four days. This substantial new snow volume and water weight has built dense, cohesive slabs across all aspects and elevations. These slabs now sit atop more storm layers that formed between March 12 to 18. 

    The most recent load is placing significant stress on a variety of interfaces (hardness changes, subtle grain type differences, and crust) in the upper snowpack, with stability teetering near the edge. Steady elevated wind speeds have also been effective at drifting the denser snowfall into deeper drifts or slabs below leeward-facing ridges and gullies. While most natural activity has likely waned, human-triggered avalanches remain likely on slopes over 30 degrees in steepness.

    (3/16/2025)

    Looking across the right flank of a skier triggered slide on an east-facing slope around 6400 feet. The slide broke over 300 feet wide and around 2 feet deep, and likely failed at either a recent storm interface or in softer snow above a sun crust. Blue Mountain, Selkirk Mountains. March 16, 2025.

    Photo: Chris Bilbrey

  • Loose Wet

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

    Warm air overtook the region Sunday night and this is quickly driving the rain line toward 7,000 feet. Fortunately, rainfall has been less across the Bitterroot Mountains as the Northern Mountains - around a half inch or less of liquid water. However, rainfall will continue and as the rain saturates deeper into the drier snowpack it will help individual snow bonds lose cohesion and be more susceptible to sluff downhill from ski or machine pressure. Wet snow hazards will grow in size, distribution, and migrate up in elevation as the warming period continues.

    The farther down slopes these wet loose slides travel, the more likely they are to entrain additional snow volume and make a larger, more dangerous pile at the bottom. If you observe natural rollerballs, the snow glops to your boards, or you post-hole past your shins into wet, rotten snow, it’s time to call it a day.

    (3/12/2025) Photo: Izzy Davis

Avalanche Discussion

While conditions in towns and valleys may seem unchanged, the mountains have undergone a dramatic transformation this week. A series of significant weather systems have reshaped the snowpack landscape. Above 4,000 feet, multiple feet of snow have accumulated over the last 10 days, accompanied by strong southwest winds that have built large cornices and extensive slabs. To add to the instability, a sharp temperature rise Sunday night turned snow into rain, saturating the snowpack and adding significant water weight to an already stressed structure. With rain expected to continue, avalanche conditions will likely remain elevated and hazardous for at least the next few days.

Today’s recommendation is fairly straightforward - the snowpack needs time to adjust to the springtime weather chaos. Don’t get lulled into a false sense of security if the obvious signs of unstable snow like cracking or collapsing are missing. Today is a great day to go bowling or work on a house project.

We are not dealing with avalanche problems that are hard to see or predict like deeply buried or lingering stubborn persistent weak layers. Instead, we have a clear hazard - large volumes of new snow sitting above diverse flavors of interfaces, not one in particular more glaring than any other. This makes paying attention to nature's clues extremely important and not allowing yourself or your group to venture near steeper terrain or below steeper hazards with no exit plan. Play a safe and conservative game in the mountains, and when stability is the question…terrain is always the number one answer.

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