Avalanche forecast

Northern Wallowas

Wallowa Avalanche Center
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Avalanche danger

Alpine
3 · Considerable
Treeline
3 · Considerable
Below
1 · Low
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Highlights

It will be possible to trigger an avalanche today as winds pick up and transport snow onto the leeward side of ridgelines and cross-load mid-slope terrain features.  It remains likely to trigger a deeper and more destructive avalanche in persistent weak layers buried 2-6' deep in the snowpack.  To avoid avalanches, steer clear of terrain steeper than 30 degrees, wind-loaded slopes, and areas that harbor a shallow snowpack (less than 3 feet).  

This forecast is sponsored by The Wallowa County Gamblers Snowmobile Club.

Avalanche problems

  • Wind Slabs

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

    Increasing winds today out of the Southwest will blow surface snow onto leeward slopes and cross-load mid-slope terrain features.  These wind slab avalanches could break up to 12-16" deep.

    Look for clues of windslab development such as cornices along ridgelines, a rippled texture on the snow surface, and a stiff feel to the snow under your machine or boards.  

    A wind slab avalanche that is triggered could add enough weight onto a slope to subsequently trigger a deeper, more destructive persistent slab avalanche failing on persistent weak layers 3-5 feet deep in the snowpack.  

    Avoid terrain that has been recently wind-loaded. 

    (1/13/2024) Photo: Caleb Merrill

  • Persistent Slabs

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

    The snowpack in the Northern Wallowas is currently weaker than the other forecast zones. Despite the warm weather and rain in late January, poor snowpack structure still exists. The possibility of triggering a persistent slab avalanche is still a very real one. The slab of snow sitting above the weak layers has continued to gain cohesion over the last couple of weeks.  This means that if you were to trigger a persistent slab avalanche, it would propagate further and be larger than you might think!   Triggering one of these avalanches would have serious consequences. If you want to avoid avalanches you should stay off of slopes greater than 30 degrees. 

    Last Sunday, forecaster Nick Burks experienced large collapses in the snowpack in the Mt. Howard area.  They were large enough to shake the snow off of nearby trees.  This is the snowpack screaming at us that it is still primed to create an avalanche.  Listen to what the snowpack is telling you.  

    Natural Persistent Slab Avalanche occuring on 1/21/24 in First Bowl.  Terrain that saw avalanches in the  Northern Wallowas 3 weeks ago have been reloading, and are not safe just because they already slid.  

    Photo: Caleb Merrill

Avalanche Discussion

Since last Tuesday, the Northern Wallowas have picked up around 10"-12" of new snow that sits above the Rain Crust that was buried on February 1st.  As time progresses, the light new snow will settle into more of a slab and could become a bit more reactive.  This will become accelerated by an increase in wind today.  

On North aspects that may be sheltered from the wind, it will remain possible to see or trigger some small dry loose avalanches.  On middle and lower elevation solar aspects that are sheltered from the wind, you may continue to see some minor wet loose avalanches as these slopes catch direct sun and warmer temperatures this afternoon. 

Be observant of how today's weather is affecting the snowpack.  Look for clues of wind loading (see above), use small inconsequential test slopes to test the reactivity of wind slabs, dry loose, and wet loose avalanches (this afternoon).  Dig down to the rain crust with your hand and get curious about how well the new snow has bonded to the Rain Crust. 

Check out an observation from last week in the Northern Wallowas here.   

WAC Executive Director/Forecaster, Victor McNeil wrote this excellent Conditions Blog. It provides a great summary of conditions in January and what that means for the snowpack now in February.

Keep the observations coming!  Let us know what you are seeing in your travels by submitting an observation here.  

 

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