Boletín de aludes

Elkhorns

Wallowa Avalanche Center
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Peligro de aludes

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

Lo esencial

Wind-blown new snow could be triggered today downslope of exposed upper elevation ridgelines.  Avoid wind-loaded steep slopes below ridgelines.  Loose snow avalanches are possible in terrain that is sheltered from the wind.  Likely remaining small, they could be dry on steep shady aspects, and wet on sunny slopes when the sun pokes out of the clouds.

This forecast is sponsored by Wallowa County Gamblers Snowmobile Club.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1–1.5

    Since Friday, 1-2 feet of new snow fell in the Wallowas, 7-10" in the Elkhorns, and 5-7" in the Blues.  This snow was combined with winds that transported this new snow onto leeward aspects along exposed ridgelines at upper elevation terrain.  On Friday, the wind was out of the South and loaded small pockets of wind slabs on northerly aspects.  As more snow developed Friday night, the winds shifted to the Northwest and loaded South and East aspects.  At upper elevations, this new snow fell onto a crusted surface that formed from last week's warm weather and rain.  This creates a good bed surface for these wind slabs to slide on.  Winds are forecasted to back off by mid-morning today, but look for signs of additional or recent wind loading. 

    Pay attention to signs of wind loading like a rippled and stiff surface, cracking around your skis and machines, and large pillows of dense-looking snow that may be below corniced ridgelines.   In areas that have received more than 10" of snow, expect these wind slabs to be large enough to bury you.  Avoid wind-loaded terrain and give the wind slabs time to relax.  

    (4/4/2024) Cracking around skis along a wind loaded ridgeline.  

Avalanche Discussion

In addition to wind slab formation in exposed upper-elevation terrain, observers yesterday noted small dry loose avalanches in steep terrain that was sheltered from the wind.  As the sun poked out of the clouds, roller balls and small wet loose avalanches were noted on sunny aspects.   Expect to see the same today.  

The amount of snow that was forecasted throughout the day yesterday didn't really materialize.  1-3" of new snow was picked up in the Wallowas and Blues, and just a trace in the Elkhorns.  In wind-sheltered terrain, observers noted little cohesion in the new snow.  Throughout your travels in the mountains this weekend, continue to monitor how the new snow is settling into more of a slab.  The new snow has seemingly bonded quite well to the old warm snow surface.  Get curious and dig down to the old crust/wet snow and see if you can pull the new snow off of this surface as a slab.  Ski or ride over small inconsequential test slopes to check the reactivity of the new storm snow.  

At lower elevations, the new snow fell on a wet surface that hadn't quite crusted up from last week's warm temperatures and rain.  The new snow has likely bonded well here, but in terrain steeper than 35 degrees if you were to get some snow to start moving from a loose snow avalanche, it remains possible that it could entrain wet snow grains and become larger and more difficult to escape.  

Cornices have grown dangerously large and recent warmer temperatures have weakened them.  They can break further back than you think.   Give cornices a wide berth, and use clues along the ridgelines such as trees and rocks to make sure you have solid ground below your feet or machine. 

Dive into more details of what we've been finding deeper in the snowpack from recent observations here.  

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We will continue to mention deeper buried weak layers that are in the form of weak snow around the 2/1 crust, now buried 4-5 feet deep under dense slabs of snow.  It has become unlikely that this weak layer will be reactive to the weight of a rider, but not altogether impossible.  The needle in the haystack scenario would include riding on steep rocky convexities where the snowpack is shallow.  Investigate what's under your feet and consider the consequences of your decisions.  

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Observations have been sparse lately.  If you are out in the mountains, add value to your forecast by submitting a public observation here.  

 

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