Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
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In sintesi

Strong winds, mixed precipitation, and fluctuating freezing levels will create dynamic conditions across the West South on Sunday. Whether wet avalanches or deeper instabilities, these slides will be difficult to predict. Your best mitigation tool will be to avoid large, steep slopes where avalanches may be more likely.

Problemi valanghivi

  • Loose Wet

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

    Another round of rain is expected on Saturday night and Sunday morning for all areas except the highest peaks and volcanoes. By this point, our snowpack has been through multiple wet days and should be able to handle the incoming water. However, wet slides will remain a concern until the surface cools.

    Look for a mix of wet problems on Sunday, such as loose slides, cornice collapses, or even blocks of snow falling from rocky ledges. In isolated areas, you may see wet slabs fail on interstorm layers from earlier this week. 

    No matter what name you give these avalanches, what we're talking about is the lingering instability of the upper snowpack due to rain and warm temperatures. 

    Any triggered wet slide will be heavy and hard to maneuver away from if you get caught. So be leery of steep slopes where they can get a head of steam and barrel far downhill.

    (1/18/2026)

    Example: A mix of wet avalanche problems from earlier this season.  Rain runnels, loose activity,  and two slabs that likely failed when snow shed from rocks or cornices collapsed above. Expect similar conditions this weekend.

    Photo: Dallas Glass

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Sunday might be the final day we have to worry about our persistent slab problem, but there's a chance this problem could go out with a bang.

    If water reaches the 2/13 or 2/7 interfaces, these weak layers could fail, similar to the wet slabs mentioned above. Or another avalanche could stress these weak layers, resulting in a secondary slide. 

    Give steep, open slopes a wide berth where these slides are more likely to be very large and dangerous.

    (3/5/2026)

    A snowprofile in the Crystal area highlighting the most recent snow, a developing crust in the upper snowpack, and our persistent weak layers down below.

    Photo: Andy Harrington

Avalanche Discussion

Sunday will be a transition day, starting with rain and ending with snow. On the volcanoes or the highest peaks, this transition may start earlier as temperatures slowly drop. With strong winds accompanying this storm, it's not out of the question that a batch of small wind slabs develop up high by the end of the day. 

This dynamic weather day has increased uncertainty around how our buried weak layers will respond. Will the wind be enough to trigger sagging cornices, creating a large trigger for these layers? Will the additional water percolate deep enough to break the bonds between the weak grains at the 2/13 or 2/7, resulting in widely breaking persistent slabs? The answers aren't clear, but keep in mind that we have a well-documented weak snowpack structure. Unusual weather could lead to unusual avalanches, so make conservative terrain choices and use good travel techniques.

Looking ahead, the cooler weather and wind should help the surface eventually firm up, putting our persistent problems to bed for the time being. It won't happen immediately, but be patient and keep an eye on the snow surface. If there's a thick, boot-supportable crust, you can probably start to ease your anxiety around triggering a persistent slab.

Coverage in the mountains remains thin. New snow will help, but may only mask problems that were previously easy to identify. Holes, creeks, bushes, and rocks are just some of the natural hazards that have plagued us all season and will continue to do so.

Regioni coperte