Boletín de aludes

Elkhorns

Wallowa Avalanche Center
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Peligro de aludes

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

Lo esencial

The likelihood of triggering a wind slab will rise during the day.  Wind slabs will primarily be found at mid and upper elevations and all aspects are on the table.  Backcountry travelers should look for snow not affected by the wind to avoid the problem and find better riding quality.  Avalanche danger is likely to increase throughout the day, especially if forecasted new snow becomes drifted into fresh slabs.  

This forecast is sponsored by M Crow in Lostine, OR.  

Problemas de aludes

  • Wind Slabs

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

    The winds look to remain consistent during daylight hours today, and the likelihood of triggering a windslab will increase, especially if we start to pick up new snow.  Remember the wind can move snow 3-5x faster than it falls from the sky.  Moderate winds (17-25 MPH) account for 80% of leeward deposition of drifting snow.  If you observe obvious signs of wind-transported snow (drifting, dune-like formations) or see shooting cracks from your skis, board, or snowmobile, avoid traveling on or under steep suspect slopes or terrain features.  

    (12/14/2024) Photo: Victor McNeil

Avalanche Discussion

Thanksgiving Drought Layer:  Each time a layer of weak snow receives a new load, an opportunity arises to learn more about whether it is gaining strength, losing strength, or staying the same.  The greatest challenge is we cannot predict the tipping point that could lead to an avalanche.  One of the best ways we can monitor a layer of concern is to dig into the snowpack, look for signs of gained strength, and perform snowpack tests.  

Uncertainty:  Unfortunately we can't scan a slope or terrain feature to determine the distribution of a suspect weak layer or the hardness of snow above it.  Some old and wise snow professionals simply choose to avoid slopes >30 degrees when a known persistent weak layer is buried in the snowpack, with a slab above it.  Across this vast landscape, we've found the Thanksgiving Drought layer gaining strength in our snowpits.  This layer is also becoming more deeply buried in areas where the wind isn't removing snow.  Weak layers need compression and insulation to gain strength.  

So what:  Using good travel protocols, exposing one person at a time, regrouping in safe zones, and sticking to terrain less than 30 degrees will greatly increase your security.  Digging a snow pit and testing the suspect layers can lure you into a false sense of security.  There is such as thing as false stable results.  A weak layer may not fail while conducting a snowpack test, but it doesn't mean the snowpack structure is good.  Remember there's so much spatial variability in this landscape, and even triggering a small avalanche with a dangerous runnout zone can have severe consequences.  

Observations:  Thanks to everyone who has submitted their observations this week.  We hope to continue this trend of receiving an increase in public and pro observations.  Remember, you are helping the forecasters fill their gaps in knowledge.  

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