Bulletin d’avalanche

Presidential Range

Mount Washington Avalanche Center
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Danger d’avalanche

Thu
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
Sans niveau
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Périmé — ce bulletin a expiré 5 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Even as the rain tapers off, continued warm temperatures will keep wet snow avalanches possible. Be cautious around steep slopes where the snow is deep, wet, and mushy as it may easily slide on a buried icy layer. Even small wet avalanches can be dangerous and destructive due to the heavy, dense weight. 

Problèmes avalancheux

  • Wet Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    What and where is it: You are most likely to find wet avalanches from saturated snow sitting on top of a buried ice crust on north, east, and south-facing slopes above 3000 feet. Continued warm temperatures coupled with yesterday’s rain may have caused snow to lose structure and wetted snow, potentially causing both wet slab and wet loose avalanches.

    How can you recognize it: Look out for areas of deeper snow that are saturated with water and may want to slide easily on hard, icy layers buried below. Signs for wet loose avalanches will be mushy, unstructured snow and rollerballs. For wet slabs, dig into the snow to see if water is pooling on an ice crust. Use a pole, probe, or your boot penetration to size the slab thickness today and use hand shears and column tests to assess sensitivity.How can you manage it: Wet avalanches can be highly unpredictable, and can still occur even after the rain stops when temperatures remain above freezing, as they are today. Give steep slopes a wide margin for error today and avoid traveling on slopes where the wet snow on the surface is soft and deep. 

Avalanche Discussion

Warm temperatures and rain persisted overnight, continuing to destabilize the snow that is above an icy hard crust. The lack of an overnight refreeze means that snow may still be unstable, even after the rain ends. As water continues to move through the snowpack and pools at the icy crust, loose wet and wet slab avalanches will be possible. Wet snow avalanches will be unlikely in areas that are scoured down to the icy rain crust from March 18th. 

On March 26th, a large wet slab avalanche occurred in Dodge’s Drop. Since wet slabs did not occur in many places, it is possible that this snow structure remains in similar steep terrain features. In the mixed precipitation event on the 26th, temperatures in upper elevations were colder, either at or below freezing. This means that you could find deeper snow on the icy crust at upper elevations. 

On the other hand, fog may limit the size of wet snow avalanches. Both the Mount Washington Observatory and Hermit Lake Caretaker reported a loss of 4 inches, with the current summit snow height at 2 inches. This is due to multiple factors, like settlement from rain and warm temperatures; however, fog can rapidly eat away at the snowpack. Today, make consistent observations as there has been a lot of change from the rain and warm temperatures. If you find deep, soft, wet snow, it could be unstable and easily slide.

While the snowpack is transitioning to a spring snowpack, it is not there yet. Wet snow avalanches should still be top of mind today, as the mountain may still be shedding snow. 

The rain, warm temperatures, and fog have continued to drive the development of various mountain hazards that should be factored into your decision-making and route planning. Large, deep, and open holes exist in many places. One of the most consequential open holes is near The Lip in Tuckerman Ravine. Learn more about springtime mountain hazards and how you could manage them. 

OBSERVATIONS: Please consider submitting an observation on our website or in the new Avy phone app of what you are seeing in your travels. Submitting an observation hones your skills, informs other users, and improves our forecasts.

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