Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Tue
Alta quota
1 · Debole
Limite del bosco
1 · Debole
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

Wind slabs may develop today as new snow accumulates. These slabs are likely to be on the smaller side, but may be sensitive and problematic on the icy, refrozen snow that exists through much of our middle and upper elevation terrain. Older, firm wind slabs escaped warming yesterday on isolated, shady aspects but are likely to be settled and unreactive to human triggering. Once again, the diurnal swings in temperature with a small amount of new snow is complicated by a significant sliding fall hazard. Avalanche danger is LOW today but beware of new wind slabs developing if you attempt to brave the howling winds in alpine areas.

 

Falling ice is a natural natural hazard in the spring.  Limit your time on slopes beneath frozen waterfalls to avoid this hazard.    

 

The lower half of Sherburne ski trail is mostly rocks and mud and is now CLOSED at the rope, currently located across the trail at crossover 5. Please help preserve early and late season skiing by removing your skis and walking down the Tucks trail from there.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1

    You’ll find recently formed slabs of wind drifted snow on mostly south facing aspects but cross-loaded onto other aspects behind wind breaks such as cliffs and bushes. These slabs are likely to be small unless snowfall totals exceed the forecast. Older and even more stubborn wind slabs can be found on other aspects in the lee of a west wind. These slabs developed late last week and have not resulted in any reported avalanches. Some of these may be on the larger side in the northern part of the range which received much more snow during that upslope snowfall event.

    These wind slabs are best described as islands of snow on an icy frozen snow surface, not a complete covering of snow everywhere. In many locations the new snow is very thin or non-existent. What remains is the older refrozen bed surface responsible for multiple skier sliding falls over the weekend with serious injuries as the result. 

    This avalanche problem may be an attractive surface to climb and ski but remember the unforgiving surface just beneath this new snow. If the lighting is good, the snow surfaces can be easy to identify: new snow will be white, clean while the icy refrozen old surface will be slightly gray in color and reflective at obtuse angles to the sun. 

Avalanche Discussion

The same aspects that were heated by the sun yesterday are now the aspects that will receive new wind loaded snow. The heat may have been slow to radiate out of the snowpack given the clouds and warmish temps overnight but should be on it’s way back to a more solidly frozen mass with the weak layer of any small avalanches likely to be within the new snow near the interface. The new snow falling today is the driving factor for any unstable slabs with wind speeds the determining factor for the location of slab development. History shows us that these slabs will be tucked into the most protected lee areas and beneath or beside cliffs. The wind speed will do a lot of scouring of exposed areas so anticipate a mix of icy snow and firm slabs. The new wind slabs may be reactive as they form but are likely to become stubborn and even unreactive later as the wind pounds rounded grains into the surface. The next several days of cool temperatures, clouds and high winds will keep long sliding falls and poor skiing conditions on tap. Warmish temperatures in the valley will be conducive to mountain biking, climbing and trout fishing;-)

You can read more about sliding fall incidents here. 

The snowpack at all elevations has changed dramatically over the past week or so due to several days with warm temperatures and rain followed by unseasonably cold weather and daily melting.

  • The lower half of Sherburne ski trail contains long sections of  mud and rocks. A rope across the ski trail at crossover #5 signals the closed trail below. Cross over and walk down the Tuckerman Ravine trail at this point. 
  • The ski trail to the Gulf of Slides is likely to be mostly bare and muddy for the first mile near Pinkham, including a few stream crossings. 
  • Increased streamflow from rain and melting snow last week has undermined snow and weakened snow bridges over stream beds. 
  • The waterfall holes and moats near rocks are growing large enough to fall into in the Headwall area of Tuckerman Ravine. The main waterfall hole and the “Open Book” ice climb hole below are both over 75’ deep. 
  • Rotten snow off trail can be knee to hip deep when not solidly frozen. 
  • The Little Headwall has melted and turned back into a waterfall with open water upstream. The safest way down from Tuckerman Ravine is hiking down the Tuckerman Ravine Trail to Hermit Lake.

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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. 

 

Listen to the weekly MWAC Outreach Podcast provided by Ski The Whites. Discussions include snowpack information, weekend outlook, and general avalanche related info. 

 

The Harvard Cabin is open for camping only with no entry allowed inside the cabin. 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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