Lawinenlagebericht

Elkhorns

Wallowa Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 2 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow and wind-blown snow from yesterday could remain sensitive to the weight of a rider today.   It remains possible to trigger a larger and more destructive avalanche in weak snow buried 2-3' from the surface.  Careful snowpack evaluation is necessary before commiting to steep slopes.  

This forecast is sponsored by Wallowa County Search and Rescue.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Dense storm snow from yesterday combined with light to moderate winds has packed the new snow into cohesive slabs in exposed terrain.  In many places, this new and wind-blown snow sits above less dense snow and/or older wind-packed layers that could make an excellent bed surface.  In areas where you find weak January facets 2-3 feet from the surface, a new snow avalanche has the potential to step down into this older snow creating a larger avalanche.  

    You are most likely to find windslabs along exposed ridgelines, underneath cornices or on exposed mid-slope features.  Look for signs such as rippled snow texture, dune-like features, up-wind locations being blown clean of new snow.  If you experience shooting cracks or whumphing of the snowpack, you are getting a free clue to dial back your terrain choices.  

    (2/5/2025) Photo: Caleb Merrill

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely
    Größe
    2–3

    It remains possible to trigger a deep and unsurvivable avalanche on the weak January facets that sit 2-3' below the snow surface.  Observers are finding mixed results in their snowpack tests, and in many places, the snowpack structure is missing a firmer bed surface layer below these facets for an avalanche to slide.  

    Treat this problem as a "low-likelihood/high-consequence" possibility and evaluate consequential terrain on a slope-scale level.  

    The most likely place to trigger an avalanche on these weak January facets will be in areas that hold a shallower snowpack with a cohesive slab of snow above them.  In some protected areas in the region, Surface Hoar has been observed sitting above the January Facets.   This set up could be particularly sensitive. 

    Persistent slabs often resist showing their hand, and may or may not offer obvious signs of instability such as shooting cracks or collapsing of the snowpack.  Continue to use careful terrain and group management techniques: Only expose one person to a slope at a time, keep eyes on, and always regroup well clear of avalanche runouts.  

    (2/10/2025)

    Crown from a natural avalanche

    Photo: Victor McNeil

Avalanche Discussion

What Happened? 

Yesterday brought 5" of new snow to the Elkhorns.  The anemometer at Anthony Lakes is likely rimed up and not reporting accurately, but it seems like winds were variable, with gusts the 20's out of the Northeast as reported by an observer in the area yesterday.   A close call over last weekend left some backcountry travelers dusting themselves off as a human triggered avalanche was reported on the shoulder of Lees above Slickrock.  This storm slab likely failed on a density change within the new snow.  Check out this recent observation from the Elkhorns. 

What's does it look like....and what is the likelihood? 

It is possible to trigger a new snow avalanche in storm snow or wind-blown snow that would be 5-12" deep.    The weight of a new snow avalanche has the potential to step down into older weaker snow buried 2-4' in the snowpack. 

To re-emphasize the Persistent Slab problem, it is important to think about each slope individually.  Carefully evaluate avalanche prone slopes before committing to them by digging down to see what's below your feet.  If you find dense and cohesive slabs above the january facets combined with a firm sliding surface below the facets- Steer clear of steep slopes.  

As the sun pops out and temperatures increase, start thinking about wet loose avalanches.   If you are seeing rollerballs/pinwheels or sinking up to your ankles in wet sloppy snow, retreat to shadier aspects and avoid riding above terrain traps. Throughout the weekend, if we get the rain on snow that is forecasted, this problem will become much more real.  

What to do about it? 

The new snow and wind-blown snow could remain sensitive today.  Hand shears, as well as riding over or ski cutting small (inconsequential) test slopes will give you a lot of information today as to how the new snow is bonding to the old surfaces.   

You will find many long-time professionals in the area still sticking to slopes 30 degrees or less to manage the Persistent Slab problem.  Continue to dig down and investigate the structure of the snowpack.  If you find hard over soft with a firm sliding (bed) surface below, you have all the right ingredients for a slab avalanche.  

Use terrain to your advantage and manage your group well. 

You can't get caught up in an avalanche if you aren't in avalanche terrain.  Evaluate the terrain carefully, and if you decide to engage in avalanche terrain, manage your communication and your partners well.  Only expose one person at a time to avalanche-prone slopes, keep eyes on them, and regroup in areas that are well clear of the runout of an avalanche path.  

It's been great to see all of the recent observations.  Keep 'em coming.  Add value to your forecast.  Submit an observation here.  

 

 

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