Bollettino valanghe

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

Rain and very warm temperatures are creating dangerous avalanche conditions. As the snowpack becomes saturated from above, water will eventually lubricate hard layers below and increase the likelihood for large avalanches to occur. The timing of these deeper failures in the wet snow are difficult to predict and the heavy dense debris would be nearly impossible to escape, so build extra wide safety margins, stick to low angle terrain, and head back to the car when you notice signs of instability.

Problemi valanghivi

  • Wet Slabs

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

    Unseasonably warm air temperatures and rainfall are saturating and destabilizing the upper snowpack. As gravity pulls the liquid water deeper into the snowpack, its progress will be halted by several impermeable hard crust layers at various depths. At each of these layers, the water is likely to initially pool up and lubricate the underside of the overlying slab. On slopes steeper than 35 degrees, the additional weight and stress combined with the reduced friction at the interface, might be enough cause a failure below the overlying slab resulting in a large Wet Slab Avalanche. 

    If the first layer does not fail, the water will simply continue its course down to the next hard interface and repeat the process of destabilization. As each hard layer becomes lubricated, the overall slab depth and density increases and in turn, the potential avalanche size and destructive potential also increases. Our deepest layers of concern are presently 3 to 5 feet deep in the snowpack. A failure at one of these interfaces would result in a very destructive and likely unsurvivable avalanche.

    (3/16/2026)

    An annoted snowpit profile showing a few of the prominent hard crust and ice layers that are found in our upper snowpack. Rainfall and meltwater will slowly percolate down through the snowpack today, and quickly work to lubricate and destablize the interfaces above these hard impermeable crust layers. On slopes steeper than 35 degrees, the added weight and loss of friction at the interfaces may result in large Wet Slab avalanches.

    Photo: Jackson George

  • Loose Wet

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

    Continued rain and above freezing temperatures are adding liquid water to the upper snowpack and weakening snow surfaces. When you start feeling the new snow sticking to your skis, boards, or sleds, or if you notice rollerballs and pinwheels fanning down across steeper slopes, that should be your signal that’s its time to migrate your mindset and terrain choices for the day. While Loose wet avalanches may start small they can grow in size. Consequences can be amplified in steep gullies, cliffs, and large road cuts, so avoid traveling directly above or below these features.

    (12/30/2025)

    Long-running Wet Loose avalanches like this may be possible across steep slopes today as rapid warming and rainfall wets the snow surface at all elevations.

    Photo: Jackson George

  • Persistent Slabs

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

    A cohesive slab 3 to 5 feet thick overlies two buried surface hoar layers. One surface hoar layer was buried at the end of January (1/28), and the other in mid-February around Valentine’s Day (2/14). The overlying slab has stiffened and settled due to wind, warm temperatures with current rain, and natural settlement within the snowpack.

    There has been no recent avalanche activity documented on these layers. However, persistent weak layers always carry uncertainty and these layers are currently being tested by warm temperatures and rain. If liquid water works its way down to lubricate one of these layers it may become reactive again, or alternatively an avalanche in the upper snowpack, or cornice fall, could provoke a large to very large destructive avalanche on one of these layers.

    (3/17/2026)This photo, recently published by our neighbors at the Flathead Avalanche Center, shows how a smaller avalanche, or cornice fall, can step down into deeply buried persistant weak layers and result in a very large and destructive avalanche. 

    Photo: Flathead Avalanche Center

Avalanche Discussion

The weather and avalanche conditions in the mountains will continue to be a roller coaster ride this week as the latest atmospheric river drives near record temperatures and dumps rain to our highest peaks. At least two inches of rain are forecast to fall in the Selkirks and Cabinet mountains between now and Friday. The abundant new snow from last week will absorb most of that, but the potential for pooling on crusts in the upper snowpack, which increases the likelihood of wet slab avalanches, has us on edge. And loose wet avalanches are possible on steep slopes at all elevations. Add to this the increasing likelihood of large cornice failures and we have several possible mechanisms to trigger very large avalanches on deeply buried persistent weak layers. Predicting the timing and likelihood of wet avalanches is challenging, but all the ingredients are in place.

If you choose to travel in the mountains today conservative decisions are essential. Wet avalanches are known for setting up like concrete when they arrest, so the threat of being taken for a ride is not to be taken lightly. With the continued rain and elevated avalanche danger, today is a great day to consider taking up an indoor hobby: perhaps you pick up where you left off several years ago in the middle of a Melville novel, or finish knitting that blanket for a niece or nephew who is now approaching double digits. Any which way, today is not the day to hang it out there and send big lines. Take it easy and be safe.

Regioni coperte