Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Cooling temperatures and increasing winds will help the avalanche danger slowly drop. However, a barrage of natural avalanches from Friday’s warm-up should still be on your mind. Be leery of very steep, rocky, and unsupported terrain as the snowpack continues through this transition.

Problemi valanghivi

  • Loose Wet

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

    It got really warm in most of the West South on Friday. Places near the Volcanoes saw significant rain. Add to that the chance for some sunshine and continued warm weather and you have a problem. Until the surface freezes, you may still trigger a wet loose avalanche in steeper areas. Most of these slides should stay small, but on longer slopes, they could entrain snow and grow larger. 

    If you encounter wet sticky snow, see new rollerballs, or find tear-drop-shaped debris, then you’ve found the issue. Potentially more concerning is the chance for one of these smaller slides to trigger a deeper, more deadly slab.

    (1/19/2024)

    Rollerballs like this show that the surface snow is becoming wet, sticky, and potentially unstable. 

    Photo: Andy Harrington

  • Deep Persistent Slabs

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

    Avalanche professional reported another very large (D3.5) deep slab avalanche on Friday. This huge slide near Colwitz Rocks (Mt Rainier) emphasizes the continued potential for isolated but devastating avalanches. 

    Weak facets persist within the Solstice Crust matrix 3-6ft (90-180cm) below the snow surface. Avalanches have been reported from every part of the zone. Even though this layer is deep, and the likelihood of triggering it is lower, the uncertainty and consequences are very high. Smaller slides, cornice falls, or finding the wrong spot could cause an entire face to come apart. Minimize the time you spend in larger avalanche terrain, including the track and runouts of bigger paths.

    (1/19/2024)

    A very large (D3.5) natural deep slab avalanche near The Cowlitz Chimneys. Other smaller (D2.5) deeper avalanches were also observed in the area.  E, 6600ft. 

    Photo: Andy Harrington

Avalanche Discussion

The mountains are in the middle of a pronounced transition from very cold to warm and wet. Saturday’s slight cool down will help, but these things take time. The recent variable weather across the zone makes it very difficult to summarize conditions. 

Deep slab, storm slab, wind slab, wet slab, wet loose, dry loose, and cornice avalanches all occurred on Friday in the West South. That’s gotta be Avalanche Bingo. On Mt Rainier and Mt St Helens, rain reached into the upper elevations. A popular travel route, Panorama Face (Paradise) failed nearly wall-to-wall with a wet slab avalanche. Near Crystal, much less rain fell and the snow produced piles of rollerballs and small wet loose slides. At White Pass, after a rash of natural storm slabs in the morning, a thin freezing rain crust formed at middle elevations during the day. If you’re head’s starting to spin with all the difference, you’re getting the picture. 

This complex and variable setup could continue, or it may just all quiet down. Exercise a bit of patience and plan your trip with plenty of options to adapt to the conditions you see.

Regioni coperte