Boletín de aludes

Presidential Range

Mount Washington Avalanche Center
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Peligro de aludes

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

Lo esencial

You could trigger a wet snow avalanche large enough to bury you as rain and warm temperatures continue to melt the snowpack. These conditions can be found on all aspects above 3000 ft in elevation. You can limit your exposure by traveling on dirty and textured snow surfaces.

Problemas de aludes

  • Wet Slabs

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

    Today’s combination of a wet snowpack, heavy rainfall, and warm temperatures could cause lingering wet slabs to fail. Currently these are limited in size, due to natural avalanche cycles, warm temperatures causing settlement and melt, and fog eating away at the snowpack. However, these slabs still have the ability to be very destructive due to the dense, heavy, and wet debris and are still large enough to bury you.

    While size has decreased, the potential for increased sensitivity from rain today still warrants careful evaluation and decision making. You are most likely to find these slabs in start zones where more wind effect might have limited some of the warming and more of the strong-over-weak structure is preserved. Identify these areas of concern by looking for planer white snow and denser structure underfoot. You can monitor surface conditions from boot penetration, hand shears, and general feel of the snow surface. You can reduce your exposure to this hazard by traveling on more dirtired surfaces.

    Gulf of Slides Main Gully

    Lingering slabs in start zones as well as dirtied snow surfaces  

    Photo: Charlotte MacDonald

Avalanche Discussion

Fog, with warm temperatures and additional rain has been eating away at the current snowpack with a visible decrease in snow coverage in steep terrain. MWOBS latest snowpack measurement from 2:00 AM March 28th reports 5 inches in height, which is 20 inches of snowpack loss from 2:00 PM on March 26th. Hermit Lake reports 18.5 inches of snowpack loss and settlement in a similar 48 hour window. 

While trending towards a spring snowpack, as seen in a temperature profile from Tuckerman Ravine, it is not yet fully there as there is still discernible structure even though an isothermal temperature profile was found in the solar aspect. The concerning strong-over-weak structure that was found Monday, is now less of a concern. This is because there was less significant hardness change found now that there has been time to settle and that meltwater has helped to compact the snow. 

Today, forecasters came to a MODERATE hazard by considering the decreased size of slabs and that the strong-over-weak composition has mostly settled. The big change today is more rain, and higher precipitation amounts expected. This additional rain will add weight to the snowpack that could act to destabilize those remaining slabs. On the other hand, while this snowpack has already seen some rain, it has seen even more meltwater and is already well saturated so any additional rain may just filter right through the snowpack. 

The biggest question is sensitivity and what will the rain do to that. Today, evaluate changing conditions, especially periods of strong and steady rainfall as this works most effectively at destabilizing the snow. Pick terrain where you can navigate the hazard of remaining slabs and assess their stability. Tonight, subfreezing temperatures will help to stabilize the snowpack, but as that will happen after daylight hours today, continued evaluation will be necessary today.  

OBSERVATIONS: Please consider submitting an observation 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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