Boletín de aludes

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Peligro de aludes

Tue
Alta montaña
3 · Notable
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 8 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Natural avalanche activity and lingering elevated winds transporting recent snowfall into stiffer slabs on leeward-facing terrain warrants continued conservative decision making. Traveling on or directly below steep northerly and easterly-facing slopes at upper elevations will increase your chance to trigger a dangerous slide. Steer clear of areas with a smooth, rounded appearance or where you see cracking in the snow to avoid a cascading scenario where a drifted slab provokes a larger, wider breaking avalanche that fails in deeper weak snow layers.

Problemas de aludes

  • Wind Slabs

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

    Wind speeds in the last 24 hours have consistently been strong enough to easily transport the abundant low-density snow on the surface into avalanche start zones and gullies. As of Monday morning, remote weather stations still report moderate west-southwest winds and stronger gusts. We expect the wind to settle down later in the day on Monday, but until it does, triggering a freshly drifted slab remains an elevated hazard in the mountains.

    Freshly drifted slabs have formed immediately downwind of ridgelines and around steep mid-slope terrain features like gully walls or cliff bands. Slab depths could vary across the same slope, but expect increasing slab depths as you move higher in elevation. Recent avalanche activity and poor stability test results continue to alert us to the threat of this problem at upper elevations.

    You know you’ve migrated on top of a drifted slab if you feel a density change underfoot, where the snow surface transitions from soft to firm. Other characteristics include a rippled or textured surface, or identified by a pillowy-shaped snow surface. If you encounter any one of these surface clues, simply steer yourself around those areas. Sticking to lower-angled or more sheltered slopes will help reduce your avalanche risk.

    (12/28/2025)

    A natural avalanche that failed in a wind-drifted part of the slope on this north-northeast aspect. The slide likely ran on 12/27 and failed in either a faceted interface from 12/24 or at the 12/19 rain crust. Slide traveled almost to the basin bottom. Selkirk Mountains. December 28, 2025.

    Photo: Chris Bilbrey

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    2–2.5

    Persistent weak layers responsible for lingering snowpack instabilities are slowly getting buried deeper in the snowpack. Even though these interfaces are showing initial signs of becoming less reactive, there is still a worrisome array of weak faceted grains surrounding multiple rain crusts. In recent days, these weak interfaces have been providing us with less and less feedback, meaning there will likely be no warning signs until a large, potentially deadly avalanche is triggered. The only way to know for sure what the structure looks like below you or how reactive it may be is to dig down and investigate. 

    Larger triggers like a machine trenching through the upper slab have a slightly higher potential to influence these weak layers than a human. Another scenario is a skier or rider finding a shallow, not-so-sweet spot on the slope like near rocky outcrops or in wind-scoured areas. Being exposed to a prolonged period of clear, cold weather conditions will allow these layers to continue to weaken. This creates a lower likelihood, higher consequence regime. Continue to make conservative terrain choices and avoid traveling in steeper, more challenging terrain to avoid an unexpected avalanche encounter.

    Recent stability tests revealed that facets surrounding different rain crusts are continuing to weaken and producing propagating failures.

    December 24, 2025.

    Photo: George LaGesse

Avalanche Discussion

After nearly two-months of steady rollercoaster-like weather, the Inland Northwest gets a chance to soak in some much-needed Vitamin D. The prior extended period wasn’t always cake and flowers, and delivered quite the array of excitement. A snowy October transitioned to a rainy November, then back to snow to start December. Then back-to-back historic Atmospheric River events reshaped the landscape and pinched our access into the mountains. Over the last couple of weeks, we’ve had to cut through a plethora of downed trees to assess the damage and learned the reality of how much snowpack we lost in the tussle of it all. Then around the holiday, and just in time for the bustling ski area crowds, Old Man Winter returned and gifted the mountains with some healthy snow.

Storm totals since December 26 range one to two feet across all forecast zones, and some higher elevation areas likely received closer to three feet of snow. Temperatures finally behaved for once and progressively lowered during the storm as precipitation engulfed the region. While this has made for improved surface conditions, it delivered a new flavor of avalanche hazard onto a snowpack with multiple interfaces of looming concern below. Concerns in the form of both thin and stout faceted rain crust where faceting around them has impressed our entire staff at how quickly they developed once buried. How reactive each one has been has varied greatly between our forecast zones and even within the same areas.

Several natural and skier-triggered avalanches have been reported recently in the Silver Valley-Bitterroots and snow safety teams in multiple areas have been able to provoke some large slides with explosives. These artificial triggers are important at this point since those operational snowpacks are very similar to the backcountry and have had hardly any snowpack disturbance or rider compaction prior. The majority of reported avalanches occurred in typical start zone areas - underneath ridgelines and where strong winds built stiffer slabs over softer snow layers, but confined to snow sitting on the Grinch crust buried on Christmas Eve. Despite the stormy period coming to an end, we expect lingering sensitivity for a bit longer in freshly drifted slabs - especially in places with new snow depths north of a foot deep.

Based on our limited field observations since the latest storm ended, it doesn’t appear that deeper persistent weak layers succumbed to the recent snow load. However, these weak interfaces remain and are  shallow enough that the upcoming period of clear, cold weather will likely help the slab above either gain strength or become more unconsolidated faster than these weak grains gain strength. This moves us into a period where signs of unstable snow will continue to diminish and wakening the monsters in the basement will become less likely, but not fully eliminated. If you are able to trigger a deeper failure, those slides will be much larger, more difficult to escape, and potentially deadly.

As the sun makes a return today and beyond, don’t let a bluebird powder day lure you into a potentially dangerous situation. Approach the mountains with a conservative mindset and stick to it. Low angle slopes that are sheltered from the wind offer excellent riding conditions - as long as they don’t reside directly below steep overhead hazards. Give the snowpack time to settle before stepping out onto or below slopes that are over 30 degrees, and curb the scarcity trap of fewer soft riding conditions days so far this season. The winter season is still young and plenty of days are ahead for fun backcountry recreation.

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