Bollettino valanghe

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Thu
Alta quota
4 · Forte
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 8 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Abundant new snow and intense wind-drifting have created dangerous conditions in the mountains where you can easily trigger a large, deadly avalanche. Avoid traveling on, adjacent to, or below upper elevation slopes where ongoing wind-drifting could provoke many slopes to fail naturally and travel long-distances downhill. If you choose to recreate in the mountains today, stick to slopes around 30 degrees or less and that provide you with an extra wide buffer below steeper overhead hazards and avalanche paths.

Problemi valanghivi

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Very Likely
    Dimensione
    1–2

    Abundant new snowfall within the last 24 hours is the primary factor contributing to the rise in the avalanche danger today. Many places received at least a foot of new snow within the past 24 hours and some mountain weather stations have reported more than 2 inches of SWE (Snow Water Equivalent). Additional snowfall is forecast to continue today and will increase the sensitivity, as well as the size and destructive potential of any Storm Slab avalanche.

     Strong southwest winds that accompanied the storm have exacerbated the problem further by drifting new snow into 2 to 4 foot slabs that will increase in thickness and sensitivity as you climb in elevation. Natural slab avalanche activity is likely today, while the additional weight of a human or machine is very likely to trigger an avalanche. Expect to find these dangerous slabs on the downwind sides of ridges and within cross-loaded terrain features.

    Stiff slabs of wind drifted snow will be building throughout the day and increasing in their sensitivity as they gain size.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    Since the New Year, cohesive 2 to 3 feet thick slabs are now stacked above several weaker snow layers in the upper snowpack. Buried surface hoar and faceted rain crusts from late-December are the most vulnerable layers for an avalanche near the surface to break deeper into. While these layers have not been tied to recent natural or human-triggered avalanches, they continue to demonstrate concerning failure potential in snowpack tests. Throw in 1.5 to 2 inches of Snow Water Equivalent into the mix and these weak, faceted interfaces should be given the respect they deserve.

     During the week-long dry period to end 2025, observations reported surface hoar formation across all forecast zones. Then a warm storm blew through on January 3 and pushed the rain line up in elevation. Rising rain levels were higher in the Bitterroot Mountains and overall snowpack wetting was more pronounced. Where rains had a deeper influence on layers below, observers have struggled to find preserved surface hoar grains. However, in the Selkirk and West Cabinet Mountains, rains did not have the same disturbing influence and those worrisome feathers remained upright and intact. Forecasters traveling in the Cabinet Mountains on Monday observed multiple propagating failures in buried surface hoar.

     Your chances to awaken one of these sleeping dragons increase from triggering a slide in the new snow that steps down or finding an area of shallower snowpack where these grains are closer to the surface but will propagate into deeper snow. Common trigger spots exist near rocky outcrops, near slab margins and on the backsides of steep rollovers. With the added load of new snow an avalanche on these layers will be large, destructive and difficult to escape.

    As new wind drifted snow piles on top of already sensative storm snow the danger of reactive slab avalanches will increase.

    West Cabinet Mountain, 1/5/26. 

    Photo: Micah Krmpotich

Avalanche Discussion

We are currently experiencing the biggest winter storm of the season, which brings with it elevated avalanche danger. The introduction of 1.5 to 2 inches of SWE (Snow Water Equivalent) to a complex snowpack, accompanied by 40mph wind gusts, has created sensitive drifted storm slabs at all elevations, with avalanche danger increasing as you climb in elevation. Today is not a good day to try to be clever and thread the needle.

Snow totals in the past 24 hours have played out close to as predicted with 7 to 12 inches in the Selkirks, 5 to 12 inches in the Silver Valley/Northern Bitterroots,12 to 17 inches in the West Cabinets, 12 top 13 inches in the East Cabinets and 3 to 7 inches in the Purcells. Given our relatively lack luster season so far, it may be tempting to want to get into all that fresh powder ASAP, but it’s worth remembering that perceived scarcity is one of the Heuristic traps common to avalanche accidents.

With December wrecked by atmospheric rivers, sub-optimal conditions during the holiday period and limited windows to recreate amid chaotic schedules, we can all relate to the desire to get the goods now, but in times of elevated avalanche danger it’s important to take a longer view and recalibrate your expectations. Showing restraint by making conservative decisions today leaves you with the potential for abundant opportunities in the long term.

Giving all the new snow and wind drifted slabs a couple days to settle and stabilize before venturing into more complex terrain is a good idea. And with a prolonged period of high pressure in the forecast outlook, there will be plenty of time to get out and enjoy the bounty of this winter storm in the days to come.

Ski and ride safe!

Regioni coperte