Avalanche forecast

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Wallowa Avalanche Center
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Avalanche danger

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

Dangerous avalanche conditions persist.  You could likely trigger an avalanche 2-5 feet deep failing on weak sugary snow that is now buried below the most recent storm snow.  This past week's storm brought plenty of new snow and wind-blown snow that has overloaded the weak snowpack structure.  The most likely place to trigger an avalanche today will be wind-loaded slopes that will have a rippled and textured snow surface, feel hollow or drumlike, or be near fresh cornices.   To avoid avalanches, steer clear of terrain steeper than 30 degrees, avoid wind-loaded slopes, and avoid avalanche runout zones. 

Today's forecast is sponsored by Quick Hatch Provisions in Joseph

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3

    It's a house of cards out there folks.  The very weak snowpack structure has just been overloaded by a significant amount of new snow and wind-blown snow.   Forecasters and observers are finding poor structure in the snowpack and reactive snowpack test results.   Check out some recent observations from the Elkhorns, Northern Wallowas, and Southern Wallowas.    We have had limited visibility in the mountains, but have heard of 4 natural avalanches being observed in the Norway Basin areas of the Southern Wallowas.  As we get better visibility today,  it's hard to imagine that we won't see evidence of a widespread natural avalanche cycle that occured during the storm.  If you travel in the backcountry today, be observant for recent avalanches, cracking around your boards or machine,  and "whumphing".   These are free bulls-eye clues and should urge you to choose more conservative terrain.   

    The scenarios that I think would most likely trigger a large to very large deadly persistent slab avalanche today would be:

    1.) Traveling on slopes greater than 30 degrees and finding a thin spot in the most recent storm snow where the weight of a rider and/or machine will stress the weak layers that are buried 2-5 feet deep.  These avalanches could run further than you expect.  

    2.) Triggering a wind slab avalanche that will bring additional stress to the weak snowpack and could "step down" to deeper buried weak layers in the snowpack.  Again, these avalanches could run further and be larger than you expect.  Within the last week, there have been two large avalanches triggered by this scenario.  One in the Southern Wallowas that was remotely triggered, and one in the Elkhorns.  See more on Wind Slab avalanches below. 

  • Wind Slabs

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

    There has been plentiful light-density snow that fell with last week's storm which has been deposited in leeward terrain and cross-loaded mid-slope terrain features.  This has formed sensitive wind slabs that will become more stubborn to trigger in the coming days.  Just because they may become more stubborn, does not change the consequences of these wind slabs.  It is recommended to avoid wind-loaded terrain. 

    If you are curious about the reactiveness of these wind slabs, find a small test slope to ride over or jump on that has a rippled snow surface, sounds hollow, or feels stiff under your boards or machine.  Look for cracking around your boards or machine.  Again, a wind slab avalanche that is triggered could easily step down into buried weak sugary snow 2-5' deep below the snow surface.  An avalanche of this magnitude would likely be unsurvivable.  

    Rippled and textured snow of a windslab cracking on a small test slope in the Elkhorns on Thusday. 

Avalanche Discussion

The storm that started last friday has deposited anywhere from 2-5 feet of new snow and was accompanied by moderate to strong winds mostly out of the West and North.   It's not the time to split hairs over storm totals.   It's enough to overload the weak snowpack structure.  We encourage you to keep the big picture simple.  A lot of snow, with a lot of wind, on a very weak snowpack structure.   

While I have dropped the Avalanche Warning today, and moved the danger rating to Considerable above and near treeline it is important to understand what that means.   Natural avalanches remain possible.  Human-triggered avalanches remain likely.   The deck is rigged folks.  Don't bet your life on it.  Careful snowpack evaluation, cautious route finding, and conservative decision-making is essential.   There is plenty of fun to be had in terrain less than 30 degrees.  

It's important to remember what human factors may be at play today within yourself and your group.   It's a holiday weekend, you may have traveled from outside of the local area, and many of us have been powder-starved for much of the winter so far.  Don't let these factors cloud your better judgement.  Make a conservative plan that leaves wide margins in the terrain you select.  Consider the consequences if you were to trigger an avalanche.  Think about the exposure of trying to rescue your partner(s) from an avalanche in the bitterly cold temperatures that we will encounter today.  

Please help develop the forecast you rely on by submitting your observations here. 

 

 

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