Avalanche forecast

Elkhorns

Wallowa Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

You can trigger an avalanche large enough to injury, bury, or kill you on wind-loaded slopes that are steeper than 30 degrees.  Recent avalanches, blowing snow, or cracking of the upper snowpack are all clear signs that wind-loaded slopes are primed to slide.  If you find yourself below the snow line, rain on snow will weaken the upper snowpack and wet avalanches will be possible.  

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Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2

    Winds are forecasted to continue to gust in the strong category today.    At upper and mid elevations, there is ample snow to be transported by the wind, and it will be building thick drifts of snow that will likely be sensitive to the weight of a rider in steeper terrain.   Good clues to wind loading are cornices along ridgelines, rippled and textured snow surfaces, cracking around your skis, and recent avalanches.   Recent natural wind slab avalanches have been observed in the Northern Wallowas in the last two days.  

    There are likely several "generations" of wind slabs from our recent storms, and some older wind slabs may still be reactive, but covered by either new snow or another round of wind slabs.  These could be more difficult to identify and will take getting off your machine or out of your boards and digging down 1-2 feet in the upper snowpack to identify recent snowpack layering.   Most of the alarming snowpack test results we have been seeing lately have been failing under a wind slab that is buried 6-8" from the surface and has softer snow below it.  (Hard over soft = unstable).

     If you ride your machine or ski across stiffened snow and stay on top of the snow, you have likely found a wind slab.  

    Avoid terrain that is or has been loaded with wind-blown snow.  Keep an eye on mid-slope features lower down from ridgelines that could be cross-loaded and be primed to catch you off guard.  Where possible, utilize small but steep test slopes to test the reactivity of newer or older windslabs. (think no taller than a single-story house with no terrain trap below).  

     

    (12/26/2024) Textured Snow and shooting cracks are clear signs of unstable and wind loaded slopes.  

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Lower elevations below 5,000' may see precipitation in the form of rain today.  If you are witnessing a rain on snow event, the upper snowpack will start to lose strength and you could start to see pinwheels or roller balls in the wet snow.  If you see this, wet loose avalanches will be likely and you should avoid steep slopes and stay out from above terrain traps such as gullies, creeks, and cliffs.  

    An observer traveled in the Western Wallowas yesterday and found wet and drizzly conditions up to 5500'.  

    (3/30/2023)

    Wet Loose avalanche into a gully.

Avalanche Discussion

The storm that started on Christmas night has brought a wet, windy, and wild period of weather to Northeastern Oregon.   Storm totals haven't been quite to the amounts that were advertised, but still significant, especially in the Snow Water Equivalent category.   See below for storm snow totals and snow water equivalent(SWE) totals.  

Blues: 13"/1.9"SWE (High Ridge Snotel)

Elkhorns: 13"/1.8" SWE (Bourne Snotel)

Northern Wallowas: 8"/.8" SWE (Aneroid #2 Snotel)

Southern Wallowas: 22"/3"SWE (Schneider Meadows Snotel)    10"/1.8"SWE (Taylor Green Snotel)

Just like most people, the snowpack doesn't like rapid change.   Give the snowpack time to adjust to the new load it has just received.  Even as significant snowfall may be tapering, there are tricky conditions out there in the form of multiple rounds of wind slabs that are in the upper 2 feet of the snowpack. Yesterday in the Northern Wallowas, our snowpack tests showed unstable results on a layer of preserved snowflakes (delicate and soft) that were hiding below an older windslab (strong and hard).  See photo below.

Strong winds have built wind slabs lower on slopes than you might expect.  At mid and upper elevations, mid-slope features may be cross-loaded.  Look for clues to wind slab development such as blowing snow, recent avalanches, cracking in stiffened snow, and textured/dune-like features.  Avoid wind-loaded areas where they overlap with avalanche paths. 

What's going on a bit deeper?   There is still the potential to trigger a deeper avalanche into older snow.  While we have a mostly right-side-up snowpack below the new snow, there are still some layers that we are keeping an eye on.  On Friday, I found reactive and propagating results from three different layers within the upper 2 feet of the snowpack.  (See a recent observation here).  These reactive interfaces were mostly below the most recent storm's snow and have the potential to be triggered from a smaller wind slab avalanche.  We call this "stepping down".   We expect these layers to heal, but best to give them some more time. 

Thanksgiving Drought Layer (TDL) We have also been tracking a weak layer that was formed during high pressure around Thanksgiving.  The TDL is a layer of rounding facets (healing sugar snow) that can be found 2-4 feet from the surface.  We have been conducting numerous stability tests to assess the reactiveness of the TDL, and we have seen this layer gain strength  This is a nice trend to see, but it is worth continuing to keep an eye on.   Suspect areas that may harbor this unstable layer are mid and upper elevations, on the northern half of the compass, and in thin snowpack depths.   You can read some recent observations that target this layer here. 

If you get out into the backcountry today, let us know what you are seeing by submitting an observation here.  

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