Boletín de aludes

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Peligro de aludes

Thu
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó last year. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Rain, then snow, now sun on my. Be ready for variable surface conditions and mish mash avalanche problems depending on aspect and elevation. The majority of terrain above 4,000 feet requires wet snow hazard management - especially where you easily sink into wet, manky snow around 6 inches or more. At upper elevations, cooler temperatures have again pushed freezing levels lower and snowfall over the last 24-hours reintroduced shallow but firm wind-drifted slabs to northerly and east-facing slopes - that now sit above weaker, likely non-refrozen wet grains. Steer clear of steeper slopes with wet, trap-door conditions, or places with a lens-shaped or pillowy appearance that produce surface cracking.

Problemas de aludes

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Higher rain totals on Monday were in the Selkirk Mountains with around an inch of liquid water. Elsewhere, rain totals ranged 0.2 to 0.4 inches before cooler conditions arrived and the precipitation flipped back to the wintery type. On Tuesday, the forecast staff found a soaked upper snowpack down 30 cm (a foot) in the Selkirk Mountains up to 6,300 feet. This pronounced wetting front may be shallower in other forecast areas that received less rainfall. Throw in another layer of fresh snow on the surface and there is ample moisture to get pumped deeper and weaken suspect layers if abundant sunny skies prevail over the next 48 hours as advertised. 

    While the origin of the wet snow hazards seems to be in daily flux - rainfall versus warm conditions driving surface melting - the presence of liquid water in the snowpack is helping weaken individual grain bonds and increasing instability in those layers. While this doesn’t really change things in terms of the “type” of avalanche problem, how to manage the terrain and when to steer clear of the likely places to find trouble may be a bit different. 

    Under warm, sunny skies following a solid overnight surface refreeze, we can monitor surface softening and begin to steer clear of sunnier slopes when the snow surface starts to get wet and punchy. Fresh snowfall has the potential to insulate the older, rain-soaked snow surface and prevent it from locking up despite below freezing temperatures. This could make for elevated odds to trigger a wet snow slide right out the gate. Rollerballs and pinwheels are indicators the snow surface is becoming vulnerable to failure from disturbance, and it’s best to dial back your slope angles or choose one's void of wet, rotten snow.

    (3/26/2025)

    Loose Wet avalanches triggered by a combination of rain-on-snow and warm, sunny weather. You can avoid these problems by steering clear of steeper slopes with a wet, trap-door snow surface. Selkirk Mountains. March 26, 2025.

    Photo: Micah Krmpotich

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–2

    Since cooler temperatures arrived overnight Monday, snow totals range 4 to 7 inches in the Selkirk and Cabinet Mountains, and 2 to 4 inches in the Bitterroot Mountains. New snow amounts may be higher in all the common leeward terrain features - beneath ridges, in gullies, and backsides of convex rolls. On Tuesday, the forecast staff found a highly variable slab distribution thanks to strong, gusty winds. To avoid an unexpected avalanche encounter, use surface clues to identify areas harboring one of these concerning drifts and be mindful of what’s below you if you were to get taken for a ride. 

    These slabs sit directly above weak (4F) wet form grains and failed with easy-moderate force in snowpack tests. Due to their shallow nature when evaluating on small, non-consequential test slopes, the forecast staff found them reluctant to fail with ski pressure. Additional slab depth from snowfall Tuesday night and these slabs could be more reactive today - especially as you climb near or above 7,000 feet. If you venture onto slopes that avoided Monday’s rain, wind-drifted slabs may be deeper and slightly more reactive.

    (3/19/2025)

    Cooler weather, snowfall, and elevated winds likely bulit fresh slabs beneath ridges, in gullies, and on backsides of convex rolles. Use surfaces clues to identify where more conderning drifts exist. Bitterroot Mountains. March 19, 2025.

    Photo: Izzy Davis

Avalanche Discussion

Recreating and accessing snow at lower elevations has become increasingly difficult as the snowpack continues to shrink, with many slopes below 4,000 feet having melted out. If you do find enough snow to travel or play on there, be especially cautious in gullies or above terrain traps, where even a small avalanche could funnel you into a bad spot and pile up quickly. As you move between 5,000 and 6,000 feet, expect to encounter another transition - springlike, wet snow has recently given way to colder, drier snow sitting atop a firm crust. Be mindful that the flavor and sensitivity of avalanche problems will be in flux within these elevations - especially on aspects where Monday’s rain will soak the drier, colder snow. As usual, the distinct rain-snow line may fluctuate regionally and within the same range with a lower elevation rain line possible across the Northern Selkirk Mountains. 

Wind-drifted slabs may still linger at higher elevations, but you’ll likely need to travel on slopes above 7,000 feet to encounter slopes that avoid the rain. Where they linger, they are likely more of an isolated concern with each passing day. The biggest concern and hazard to manage with older drifted slabs is whether they are simply soaking up the rain and becoming more settled to the crust below, or are they getting wet enough to fail as a more dangerous Wet Slab avalanche. The latter would be the more likely scenario across a broader area given today’s weather, and enhanced by water percolating to the crust and acting as a sliding lubricant.

On a typical spring day, the rate of softening is often dictated and exacerbated by the sun, which gets progressively higher in the sky with each passing day. Rain-on-snow has the potential to accelerate meltwater to weak layers and help soften refrozen crust below, and push wet snow hazards deeper into the snowpack. Continually monitor how punchy or rotten surfaces get to stay ahead of the wet problem game. Slopes where you see large glide cracks, give an extra wide buffer or simply go around. Additional snowpack water weight from rain can push these slopes closer to failure and the timing of glide avalanches is notoriously unpredictable.

In some ways, a spring snowpack can be easier to understand because temperature and solar radiation are key drivers of change. How firm or soft surfaces are at the beginning of your mountain adventure often provides valuable insight into when and where conditions may become dangerous, if at all. Monitor how overall conditions change from start to finish, and avoid high-consequence terrain when stability is in question. Small slides in steep, committing terrain can have serious consequences, so continue to make cautious, well-timed decisions as the season transitions.

**Eastern Oregon University is conducting a survey to better understand avalanche safety preparedness among motorized backcountry users. The survey will help us learn more about who is purchasing, and practicing with avalanche rescue gear (beacon, probe, shovel) and participating in avalanche education—and why some riders are not. The survey is confidential and anonymous. Your feedback is invaluable to improve avalanche education and awareness across North Idaho and Northwestern Montana. Please take a moment to share your experience and help your local avalanche community. You can take the survey HERE.**

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