Boletín de aludes

Presidential Range

Mount Washington Avalanche Center
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Peligro de aludes

Sun
Alta montaña
2 · Moderado
Límite del bosque
3 · Notable
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Several days of snow, combined with several days of west and northwest wind have worked to drift snow onto eatern aspects, creating dangerous avalanche conditions. Human triggered avalanches are possible today in many middle elevation areas, and could be large in some locations including Tuckerman Ravine and the Gulf of Slides. Stick to firm, wind-impacted surfaces or shallow drifted snow to avoid the avalanche problem today.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2.5

    Large wind slabs up to 3 feet thick formed from recent snow remain sensitive to a human trigger today primarily in east-facing ravines at middle elevations. Look for pillowed or drifted areas on the lee sides of ridges, gully walls, and other terrain features. Smaller avalanches may step down deeper into the upper snowpack creating a larger avalanche. 

    With the current snow hardness, shooting cracks are unlikely to present themselves.  An absence of shooting cracks today should not be taken as a sign of stability. You can initiate an avalanche in areas where the firm slabs thin, and they have the potential to break above you and around you. Recent avalanches on similar aspects are a red flag for this avalanche problem. 

    If skies remain clear in the afternoon, and warming occurs on south facing slopes, be prepared for decreasing stability. 

Avalanche Discussion

Field time yesterday began with investigation of a fairly widespread natural avalanche cycle on east facing terrain likely occurring on Thursday, and a human triggered avalanche in Tuckerman Ravine. Forecasters observed evidence of recent natural avalanches on several slopes all generally east facing.  

At around 11:30 an experienced solo skier triggered an avalanche in Sluice, Tuckerman Ravine. The hard slab was triggered at a thin spot near a rock buttress and propagated above and into a deeper slab of snow. The resulting avalanche was in the D2-2.5 range and likely failed on a thin weak layer of softer snow found within the recent snow. In the avalanche path, some areas of frozen bed surface are exposed meaning the avalanche “stepped down” and entrained slabs formed earlier in the week. Stability tests performed nearby on a similar aspect and elevation failed at ECT10 & 11 on that same thin weak layer 45 cm down. The skier was unhurt and remained on top of the snow. 

Careful decision making will be required when traveling in avalanche terrain today. Strong wind has worked to harden surface slabs in the most exposed locations, reducing the chance for triggering a slide. However, variability from terrain features, combined with several days of slab formation on slightly different aspects will challenge safe travel.  

Thanks to everyone for taking the time to submit observations of snow and avalanche conditions, both inside and outside our avalanche forecast area. Please keep them coming.

The Lion Head Summer Trail is closed for the season due to avalanche risk. The Lion Head Winter Route is open.

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