Bollettino valanghe

Elkhorns

Wallowa Avalanche Center
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Pericolo valanghe

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

In sintesi

If you head to the top of the peaks, or into more complex terrain in the alpine, you may be able to trigger a lingering unstable wind-loaded pocket. 

It is with profound sadness that we report an avalanche fatality occurred yesterday afternoon in the Northern Elkhorns. Our backcountry community is small and understand the tremendous grief many are experiencing. Our thoughts and prayers go out to all affected.  An accident report will be forthcoming in the next few days.  A preliminary report can be found below in the forecast discussion.

This forecast is sponsored by Anthony Lakes Mountain Resort. 

Problemi valanghivi

  • Wind Slabs

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

    Isolated pockets of reactive wind slab several feet thick may still exist near and below ridgeline at upper elevations on NW-N-E aspects. The effects of recent wind-loading may present as smooth hard pillows lurking below ridgelines or sub-ridges mid-slope, as cornices hanging imposingly over steep slopes, or if settled powder snow gives way to stiff punchy windboard. These are all the signs of potential wind slab. The lack of significant new snow or wind are helping the wind slabs stabilize. However, danger may lurk in isolated pockets. Look for and avoid steep slopes (>35 degrees) with large overhanging cornices, smooth textured wind pillows, and/or deposition zones with convex rollovers. 

     

    (2/29/2024)

    This is the dappled texture of a classic wind slab. 

    Photo: Wallowa Avalanche Center

Avalanche Discussion

Avalanche Fatality on Gunsight Mountain in the Elkhorn Mountians on 3/6/24

At approximately 4:30pm on Wednesday, March 6th, an avalanche accident occurred on the north side of Gunsight Mountain (8342') in the Elkhorn Mountains near Anthony Lakes.  Union and Baker County SAR units responding to the incident.  Unfortunately, the victim succumbed to injuries at the avalanche site. 

A full investigation and report will be forthcoming in the coming days.  Our backcountry community is small and we understand the tremendous grief many are experiencing. Our thoughts and prayers go out to all affected. 

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A pesky and persistent layer of buried surface hoar lurks in isolated pockets on mid-elevation NW-N-NE aspects. The layer of surface hoar buried on 2/26 has been found in the Elkhorns, Southern Wallowas and Northern Wallowas. Propagating results were observed in Extended Column Tests on this layer on Saturday (3/2) 50cm down. Sunday (3/3) I found buried surface hoar mixed with graupel sitting on top of the 2/26 crust at 7500' on a NE facing slope in the Northern Wallowas down 80cm. This layer failed in a Compression Test and propagated in an Extended Column Test in extra innings (more than 30 hard whacks from the shoulder).  While the distribution of these layers is patchy, it does exist and could be reactive to the weight of a rider.  Before committing to terrain over 35 degrees with steep convexities it is advised to dig down to look for this layer. It usually presents as a very thin and barely visible layer in the snowpack and takes time evaluate. 

There is a slight chance that the fair amount of light density snow present could become moist with daytime warming, loose cohesion, and move down steep south-faciing  slopes > 35 degrees as wet loose avalanches at lower elevations. Wet loose avalanches or sluffs can carry you to places you don't want to be. Look for rollerballs and pinwheels as visual clues of wet loose avalanches. If you see these signs or start sinking into the wet snow seek lower-angle slopes or slopes without terrain traps in case you take a ride. 

This is the time of year when extra caution should be given to overhanging cornices. As temperatures rise and the sun's power grows more intense cornice fall becomes an elevated hazard. Give cornice edges wide berth, and when traveling on ridges, always stay on the windward side where signs of terra firma exist - a tree, a rock, - something to let you know your not dangling in space and tempting fate. 

For future reference: Relatively calm conditions for several days combined with clear cold nights have produced surface hoar crystals on W-N-E aspects well up into the alpine. When we start to get significant snow again this buried layer of surface hoar could become an avalanche problem. When out touring today pay attention to where you are seeing significant surface hoar formation and tuck that little tidbit in your memory bank for future retrieval. 

 

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