Boletín de aludes

Elkhorns

Wallowa Avalanche Center
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Peligro de aludes

Mon
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

It is likely to trigger an avalanche on wind-loaded slopes, with natural avalanches possible.  If a small wind slab is triggered, it is possible it could produce a larger avalanche down 2-4 feet.  Safer travel is found in lower angle, wind-sheltered terrain.

This forecast is sponsored by Anthony Lakes Mountain Resort

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    Wind slabs remain the primary avalanche concern today. While winds will be calmer today, they will still be strong enough to transport fresh snow, keeping these slabs sensitive to a rider’s weight. Stay cautious when you notice firmer, wind-stiffened snow or dune-like drifts, as these are signs of wind loading.  Avoid steep slopes with these indicators and watch for blowing snow.  If you trigger one of these wind slabs, you could trigger a higher consequence persistent slab avalanche.  

    Photo: SD

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–2.5

    Weak snow is buried 2–4 feet below the surface, and while we haven’t seen much recent activity on these January facets, they shouldn’t be ignored. They’re called "persistent" for a reason—just because you don’t observe whumpfing, cracking, or natural avalanches doesn’t mean the problem has gone away. Even if snowpack tests don’t produce alarming results, the overall structure remains concerning. This weak layer is widespread across all zones, buried at varying depths and topped with slabs of differing hardness, making forecasting difficult and increasing uncertainty. If you find a spot where the weak snow is closer to the surface with a slab above it, the resulting avalanche could be large and destructive—something you don’t want to experience.

    This very fragile weak layer was found under 2' of Feb storm snow on an East Aspect at 5,300' in the Blues.  

    Photo: Victor McNeil

Avalanche Discussion

Over the past few days, snowpack tests have revealed storm snow failures at varying depths. Observations submitted yesterday ranged from collapsing and failures in compression tests to no notable results in snowpits. These mixed findings add to the uncertainty in our snowpack. When uncertainty is high, it's wise to scale back exposure and increase safety margins.

Avalanche terrain is a tricky, high-consequence learning environment—you might see no obvious signs of instability and still hit the "needle in the haystack." Weak snow exists at different depths and hardness levels, making conditions unpredictable. A lack of alarming test results does not mean a slope is safe to ride. Spatial variability is particularly high right now, meaning one spot may have no slab over weak layers, while just a few feet away, a slab is sitting on top of them. Winds have formed these slabs on ridgetops and even mid-slope, increasing the risk of avalanches. Stay curious, keep assessing the snowpack, and be cautious in your terrain choices.

Uncertainty:  As forecasters we often discuss uncertainty, and as this increases the best solution for managing ourselves is terrain.  Terrain and where we choose to travel is the only element we have control over.  Because of spatial variability, we have no way of knowing what the snowpack structure is beneath us unless we dig.  Even then we could slightly change aspects or elevations and find changes in the snowpack.  With poor snowpack structure, we should increase our margins, dial it back, and slow down.  If you are interested in this topic we suggest you take a look at this article titled, "Users' Awareness and Response to Uncertainty Information in Public Avalanche Forecasts."

Snowpack considerations: When the weather becomes erratic, so does the snowpack.  Strong to extreme winds in many parts of our forecasting zones have left us with variable depths of wind slabs, especially in more open terrain features.  You're likely to find wind slabs in locations where you wouldn't normally expect to find them.  The January Facets haven't really come alive, but each time we have a significant weather change they are back on the table.  This is a good time to hit the reset button on the way you view terrain that maybe you've been riding in, on, or around.  If you are visiting this region for the first time this winter, spend some time digging into the snow and look for strong snow, overriding soft or weak snow.  

The January Facets are pronounced at mid and low-elevation terrain on all aspects.  If you dig into the snowpack, you'll see them below the Feb. storm snow.  We've been receiving inconsistent results in our various snowpack tests, primarily because there hasn't been enough of a slab above the weak facets to observe failures.  This is considered a false positive result because anyone who's been around snow long enough knows that persistent grains (surface hoar, depth hoar and facets) are dangerous and unpredictable.  If you find a location with a more cohesive slab above the facets you may see failures in your testing.  Triggering a surface instability (wind slab/storm slab) increases the odds of a much larger avalanche failing or "stepping down" to the Jan. facets and in some locations 1/31 Buried Surface Hoar.

 Submit an observation to help WAC Forecasters reduce uncertainty. It can be short, simple, and even anonymous. Any information you have will help us write more accurate forecasts that will, in turn, better help guide your backcountry decision-making.

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