Boletín de aludes

Stevens Pass

Northwest Avalanche Center
Ver en el mapa

Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
1 · Débil
Bajo el límite
1 · Débil
Open full map
Desactualizado: este boletín caducó 3 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Conditions are challenging with a breakable crust in all but the highest elevations. If you manage to get above the rain line you might still be able to trigger a slab avalanche. Travel cautiously in the crust,  and look for signs of instability like whumphing collapses or shooting cracks before committing to steeper alpine terrain.

Problemas de aludes

  • Storm Slabs

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

    The recent storm laid down 2ft of new snow, but it ended warm with light rain up to at least 6,000ft. In the true alpine islands of the zone, you might get above the crust and find lingering instabilities in drier snow. Slabs could be as deep as the new snow over a pronounced crust, roughly 2ft in most places but they could be deeper in heavily wind drifted areas. Especially consider steep slopes near ridgelines or near cornices to be of concern. Other features to identify for caution are mid-slope convex rolls, and steep slopes beneath cliff bands. 

    If you do make it up high, this is a great time to dig a snow profile. Look for weak layers in the snowpack, and test how recent layers are bonding. The storm snow may be resting on slick crusts and surface hoar in isolated areas. You can also use quick hand pits to look at layering. Small, inconsequential test slopes may also help when looking for instabilities like shooting cracks. 

     

     

     

    Example slab avalanche from a higher elevation slope in the Chiwaukum Range. December 19,2021. 

    Photo: Matt Primomo

Avalanche Discussion

Since last week Stevens Pass has received over 2ft of new snow. Unfortunately the storm ended on the warm side with light rain to at least 6,000ft. A widespread cycle of wet loose and wet slab avalanches was observed, and many slopes ran with a variety of avalanche sizes from small to large. Some of the more impressive slides were these wide slabs on the backside of the unpatrolled, unopened ski area on a run known as Aquarius Face. This was a solid D2 (large) avalanche with a crown at least 600ft wide. With clearing skies and cooling temperatures, the surface crust should refreeze and stabilize most slopes on Tuesday.

Our uncertainty liese at higher elevations, once you get above the rain crust. What elevation does it extend to? Is the storm snow/wind drifted snow bonding poorly to slick old crusts or buried surface hoar? These are all questions to answer if you find yourself up in the alpine with this fairly benign weather. Don't commit to larger slopes before first seeing how the snow reacts on smaller, lower-consequence slopes. As you travel, carefully observe and look/listen for signs of instability like collapsing or shooting cracks.

If you make it out, please let us know what you found by submitting an observation here. Thanks!

Regiones cubiertas