Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
Senza grado
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Watch out for smooth, white wind drifted snow on easterly mid-elevation aspects. Larger drifts may hold enough snow to bury a person if triggered. Warm temperatures above freezing in the ravines will work to decrease stability in the new drifts, making them easier to trigger.

Problemi valanghivi

  • Wind Slabs

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

    An additional 1.5 inches of snow early yesterday combined with the 1.8 the day before, gives yesterday’s northwest wind just over 3 inches of snow to blow into eastern ravines. Fresh wind slabs 1-2 feet thick will likely be more sensitive than stubborn due to moderate wind speeds. 

    Evaluate the depth of the slabs as you travel, you should be able to steer around any deeper pockets to avoid this avalanche problem. Warming today at mid elevations will work to decrease the stability of the new slabs, requiring constant evaluation of snow depth and wetness. Keep in mind that a slope skied at 9am may be unsafe at 1pm due to warming.   

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    New snow on south aspects will warm from the sun and become wet. Roller balls in steep terrain are an indicator for this avalanche problem. These wet loose sluffs will be small in size but can pull you off your feet if not managed appropriately. 

Avalanche Discussion

Wind slabs formed late last week were warmed and then refrozen, reducing concerns for a larger avalanche pulling deeper into the snowpack. Today’s avalanche problems are mostly limited to the 3 inches of new snow that fell Sunday night and Monday morning. 

The main avalanche problem for today, Wind Slabs may be considered a place-holder for a slab which may fail in some fashion. Early in the day, these drifts of dry snow can be triggered by an additional load exceeding the bonds holding the slab in place on the slope. For our purposes, the additional load is likely a human. Later in the day as the snow surface warms and free water is introduced into the snowpack, the bonds holding the slab in place on the slope may weaken, meaning that the slab will be easier to trigger. Given enough warming, and more free water, the bonds holding the slab in place may fail on their own without a human trigger and could be considered a Wet Slab. Either way, the result is a slab avalanche which will be difficult or impossible to manage if triggered. Be mindful of the potential for decreasing stability throughout the day. 

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.

  • The John Sherburne Ski Trail is closed before the last hill. Please cross over to the Tuckerman Ravine trail at the yellow rope and walk down the hiking trail.
  • The Harvard Cabin is closed for the season.
  • The Lion Head Summer Trail remains closed for the season due to avalanche risk. The Lion Head Winter Route is open.

 

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