Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Sat
Alta quota
1 · Debole
Limite del bosco
2 · Moderato
Sotto il limite
Senza grado
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Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Extreme winds transported the seven inches new snow that fell over the past two days and packed it into wind slabs in lee terrain. These wind slabs will be firm and are likely to be unreactive in most areas. They’ll  be largest lower on slopes due to scouring above but could be dangerous over any consequential terrain. The largest wind slabs will be found in Tuckerman Ravine and the Gulf of Slides, both of which are downwind of the most expansive fetch in the range. These areas have MODERATE avalanche danger with human triggered avalanches possible. Throughout the range, new, wind deposited snow will be obvious in contrast to the old, gray snow surface. The old snow is the dominant surface in avalanche terrain and is hard and icy. Wind speeds near and above treeline will make it particularly challenging to travel on this icy surface today. 

The summer Lionhead Trail is open for travel, but may have wind slabs to deal with on the steep and icy snowfield near treeline. 

Federal regulations require the use of a face mask on public lands when social distancing is not possible. Please have a mask handy for busy times on the deck and courtyard at Hermit Lake and even the floor of Tuckerman Ravine.

Problemi valanghivi

  • Wind Slabs

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

    Stubborn wind slabs pepper the terrain with some larger wind slabs downwind of prime fetch. These wind slabs are likely to be mostly stable but continue to use safe travel techniques as history shows us that triggering the firm slabs that follow extreme winds is unlikely but not impossible.

    Looking up from the upper Sherburne entrance to Hillman's Highway with the Dodge's Drop exit visible in the distance. This part of Hillman's is scoured during even lower wind speeds than we had overnight so it's no surprise to see them scoured to the rock hard old snow. What isn't visible is the choke up near the fork. That is where I'd expect to see the largest, unavaoidable expanse of wind deposited snow.

Avalanche Discussion

Limited visibility and few observations creates some uncertainty around  the extent of new wind slabs.  The pivotal piece of information is the extent to which the areas of fetch produced the necessary loose snow to build larger slabs. A little over a week ago, the alpine zone was bare but since that time winter conditions and new snow have filled in this area to some extent. Observations from the caretaker this morning of Hillman’s HIghway below the dogleg revealed that this area was heavily scoured, which isn’t unusual after winds hit the century mark. Unfortunately, fog obscures the mid and upper start zones but past experience in the terrain tells me that the new wind slabs today could approach the large (D2) size, but only in a few areas. 

If you are reading this far past the section of the forecast which describes 80-100mph wind today, it’s likely that you’re making decisions about tomorrow. Warm temperatures on the summit certainly favor softening of the snowpack, but factor in the cold snowpack after 36 hours of well below freezing temperatures. Some cloud cover may delay softening too. Both factors may actually aid in creating good, and not sloppy conditions. JUst be sure to account for variable conditions include hard and icy conditions in the shade and lingering instabilities in recent wind slabs.

The typical spring hazards emerged in recent weeks and should remain a player in your travel plans. New snow may bridge over some of the hazards which include: 

 

Regulations on Federal public lands supersede state mandates regarding protection from the coronavirus and it’s variants. These regulations require the use of a face mask when social distancing is not possible. Please plan to wear a mask in busy areas like the deck and courtyard at Hermit Lake and the floor of Tuckerman Ravine on a busy day.

 

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Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at MWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

 

The Harvard Cabin is now closed for the season. There is no access to the breezeway at HoJos.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This forecast is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Avalanche danger may change when actual weather differs from the higher summits forecast.

For more information contact the US Forest Service Snow Rangers, AMC visitor services staff at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or seasonally at the Harvard Cabin (generally December 1 through March 31). The Mount Washington Ski Patrol is also available on spring weekends.

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