Boletín de aludes

Presidential Range

Mount Washington Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

New snow and strong winds will increase the risk of avalanches in steep terrain across the Presidential Range today. Look for blowing snow to create unstable pockets of drifted snow in upper and middle elevations in wind sheltered areas. Staying on lower angled slopes and out of avalanche run-out zones will help you enjoy a safer day in the mountains.

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–3

    As winds increase throughout today expect the new snow to be eroded from the landscape and transported to slopes on the leeward side of the mountains. South winds are not usually a producer of large slabs in the eastern ravines, but as the winds shift more westerly and gain strength, that will change this afternoon. If we get visibility today look for banners of snow streaming from ridgelines as an indicator of where the snow is being transported. 

    Currently, and before the winds ramp up, snow is collecting on the alpine fetch for later redistribution to the slopes below. The amount of snow gathered up high can exponentially increase the size and distribution of slabs in the steeper terrain with the wind's influence. This afternoon's extreme winds may correlate to slabs growing several feet thick in the skiable terrain of the middle elevations. Expect increased sensitivity in the slabs below ridgelines where natural avalanches are most likely.

  • Storm Slabs

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

    Moderate south winds on the higher summits and calm winds at the lower elevations will allow the new snow to stack up on all aspects, at least early in the day. Before afternoon winds whip up the new fluffy snow and transport it to leeward slopes, expect new storm slabs to form over a variable surface snowpack. Yesterday’s exposed ice could act as today's slick bed-surface for avalanches to slide on, as the slabs grow in mass and become more unstable. Recent wind drifted snow below these growing slabs may also have the ability to fail under the weight of new snow. Graupel and moderately sensitive results on observer’s stability tests in drifted snow, are red flags for those traveling in steep terrain today.

Avalanche Discussion

As storm totals slowly fail to reach their initial expected accumulations, we still have a Considerable avalanche danger for the Presidential Range. Enough snow has fallen already in the mountains to warrant caution on the steep ravines and leeward slopes. It should continue to snow throughout today and into tomorrow with the slight chance for freezing rain this afternoon.

Yesterday’s observers noted sensitive slabs of wind drifted snow in specific distribution across the slopes. Variable in surface consistency, the wind drifted slabs showed some ability to fail under moderate forces in multiple locations. Graupel, over 5mm in size in some locations, was apparent rolling downslope and found pooling at the base of steep and confining gullies. These are the warning signs to look for during pre-storm conditions and may contribute to an overall lack of snow stability as you ascend in the terrain today.

Pay close attention to the clues and anticipate poor visibility from clouds and blowing snow. Sensitive slabs may be found lower on the fan of steep terrain and remote triggering is possible later today. Drifted snow could grow very deep on leeward slopes, with avalanche size and destructive potential becoming large. 

The Lion Head Summer Trail is CLOSED due to increased avalanche hazard. The Lion Head Winter Route is OPEN and the most direct route to the Mount Washington Summit from Pinkham Notch. 

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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