Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

You could trigger a large avalanche on steep slopes above 3000 feet in elevation. Recent avalanches nearby, deep drifts of new snow, and shooting cracks under your feet are all signs of a dangerous snowpack. Conservative decision making and minimizing time spent in or underneath large open snow slopes is essential for safe travel today.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    What and where is it:New wind slabs between 1 - 2 feet thick may be found in north and east-facing terrain above 3000 feet. These slabs are made up of newer and softer snow from wind transportation over the past 3 days. Avalanches in new, softer drifts could have the ability to step down into a harder, older, more destructive persistent slab on top of a slick melt-freeze crust.How can you recognize it: Newer wind slabs from snowfall and wind transport over the past 3 days are likely to be softer and appear smooth and rounded. Signs of instability include deep, penetrable drifts, shooting cracks, and have a hollow feeling or sound.  How can you manage it: In areas where you find connected drifts deeper than your boot tops, use quick hand shears or column tests to check how well the slab is bonded to the snow below. Minimize time spent underneath large, open snow slopes and make conservative terrain choices if you choose to travel in or around avalanche terrain.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–2.5

    What and where is it:Old, hard slabs are sitting on top of a slick melt-freeze crust formed on January 10th. In many areas, these slabs are hidden underneath recently formed wind slabs. The most likely place to find this avalanche problem is between 3000 and 5000 feet on easterly aspects. 

    How can you recognize it: This avalanche problem will be difficult to recognize just by looking at the snow surface and it is not likely to give clear signs of instability unless you dig down into the snowpack to assess. This slab will appear harder and more supportable than softer recent wind slabs. Dig down to the hard, slick melt-freeze crust and look for a thin layer of weak snow in between the hard slab above and the crust below. 

    How can you manage it: Understand that even though this avalanche problem may be difficult to trigger, finding an invisible thin spot in the snowpack has the potential to release a large, hard, destructive avalanche. Factor this avalanche problem into your own risk tolerance and decision making today, realizing that if a smaller avalanche occurs on top of this slab, it could have the ability to step down and create a larger, more destructive avalanche.

Avalanche Discussion

The snowpack is complex and will take careful evaluation and smart terrain management to move safely in avalanche terrain today. Recent wind slabs on the snow surface will be the easiest and most obvious avalanche problem to identify today. While the likelihood of triggering a windslab avalanche is decreasing, they have the potential to be large and could step down into a deeper weak layer and create a larger avalanche. 

At middle elevation, easterly snow slopes have a harder slab sitting on weak snow on top of a crust that is hidden below the surface in many areas. Over the past several days, avalanches have occurred on this layer in Tuckerman Ravine, Summer Lion Head Trail, and the Gulf of Slides. Signs of this deeper instability have been observed in other east-facing, middle elevation areas that have yet to produce an avalanche.

There is an unpredictable nature to this hard, persistent slab and signs of instability may be hard to find until it is too late. Over the next several days, very cold temperatures could keep the deeper weak layer from effectively bonding together with the hard crust. As winds increase significantly tonight and allow for additional snow transport and slab formation, new slabs could continue to add stress to the buried weak layer in the snowpack and avalanche danger could be elevated by the morning hours.

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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