Bulletin d’avalanche

Presidential Range

Mount Washington Avalanche Center
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Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 8 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Large natural avalanches are possible today on east-facing slopes above 3,000 feet due to wind loaded snow. Reduce your exposure by minimizing time spent beneath avalanche paths in east-facing ravines.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    What and where is it: Around 6 inches of new snow over the last 48 hours, with an additional 2 -4 inches today, will be rapidly redistributed by strengthening northwest winds. Expect wind slabs to form on lee and cross-loaded terrain, especially on easterly facing features such as Tuckerman Ravine, the Gulf of Slides, and Huntington Ravine.

    How can you recognize it:  Visibility is expected to be poor at times, so identifying wind slabs, especially near ridgelines may be difficult. You may not be able to see wind loading happening high in the start zones, but recent snow available for transport and increasing northwest winds are key warning signs that slabs are forming. With visibility look for fresh, smooth wind drifted snow: pillows, rounded drifts, and stiff slabs. Shooting cracks and hollow or drum-like snow are strong indicators you are on a wind slab. In the most wind-loaded locations, slabs may be up to 2 feet thick.How can you manage it: Today is a day to be conservative. With poor visibility and active wind loading, you may not be able to see start zones or accurately judge growing slabs near ridgelines. Manage this problem by avoiding steep lee and cross-loaded terrain where slabs are most likely to form, and by minimizing time spent beneath large avalanche paths and in runout zones.

Avalanche Discussion

Over the past 48 hours, the snowpack has received roughly 6 inches of new snow, with an additional 2-4 inches expected today. This snow is low density and highly transportable, and strengthening northwest winds are actively redistributing it into lee and cross-loaded terrain. Some model guidance suggests the potential for higher snowfall totals today, which would extend the period of loading and allow thicker wind slabs to form. If that scenario verifies, the result would be a higher likelihood of larger avalanches and a longer window of natural avalanche activity as loading continues.

The avalanche hazard trend over the next two days hinges on how much snow ultimately falls today and how long winds remain strong. If winds reach the upper end of the forecast for more than a few hours, we expect widespread scouring at upper elevations, potentially stripping snow down to the recent melt-freeze crust formed during the last rain event. That outcome could reduce avalanche hazard tomorrow in wind-exposed higher elevation terrain. However, until loading ends, today remains a period of elevated avalanche hazard.

Given these conditions, the big-picture signals matter most today. Increasing winds, active snow transport, and new snow available for loading are the primary red flags, and they outweigh the value of searching for subtle instability clues. In many places, attempting to dig or test the snowpack in representative drifts would require standing in or beneath avalanche terrain, increasing exposure to overhead hazard. Conservative terrain choices, minimizing time under avalanche paths, and avoiding steep lee terrain during active loading are the most effective risk management tools under these conditions.Vermont: Yesterday we received three Vermont observations that show the recent snow is reactive on top of the recent rain crust. Smugglers Notch reported weakness in tests, Jay Peak had a small human triggered slab, and Mount Mansfield reported cracking and multiple small avalanches. Green Mountains North

Holiday note:From all of us at the Mount Washington Avalanche Center, we wish you a safe, fun, and avalanche free Christmas and holiday season. Whether your plans involve skiing, climbing, hiking, or simply enjoying time with friends and family, we hope you get out, have fun, and return home safely. Thanks for taking the time to read the forecast and for helping keep the mountains a safer place for everyone.

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