Lawinenlagebericht

Presidential Range

Mount Washington Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
Keine Stufe
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Veraltet — dieser Lagebericht ist 4 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

New snow that fell above 3000 feet has been wind-transported to the eastern slopes of the upper and middle elevations. Slabs of drifted snow in steep terrain could fail with the weight of a human trigger, causing a large avalanche. Use hardness and visual clues to investigate the slabs you encounter as you climb into committing terrain.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Around 4.2 inches of new snow fell yesterday with strong winds. Initially the winds came out of the south, shifted west, and eventually gusted to 69mph and sustained out of the northwest. Precipitation started as rain and sleet for the low and middle elevations and light snow for the upper elevation summits. Slabs of wind-drifted snow have collected on aspects facing north through east through south, and could be up to 1 foot thick. A myriad of different precipitation types fell during the storm, so expect changes in density throughout the most recent surface snow layer.

Avalanche Discussion

Enough new snow has fallen in Tuckerman Ravine to warrant a Wind Slab avalanche problem. The distribution of the slab is specific to terrain on the eastern aspects of the upper and middle elevation slopes. Expect a reactive nature to the slabs sensitivity, meaning that human triggering is possible. With some slabs reaching depths of 1 foot in some locations, if triggered you are potentially looking at an avalanche with the destructive size capable of burying a person.

Warm air allowed for wet snow during the start of the storm which changed to rimed particles and dry snow to follow. This snowy sequence helped create a right-side-up layering scheme which made for good bonding to the older snow surface. The surface snowpack remained moist and superficially unfrozen up to 4000 feet in elevation until 2pm.

The issue facing many skiers in the ravine yesterday was the partially refrozen avalanche debris that is scattered throughout the terrain. The hard wet slab avalanche that occurred on March 31st has enveloped the floor of the ravine with large chunks of unavoidable debris. Several smaller loose wet avalanches poured out of places like Right & Left Gullys leaving behind a snail-trail of obstacles in their run-outs. When visibility is low it’s best to check your speed.

Also keep in mind that melting has occurred over the last few days, bringing springtime objective hazards to the forefront. If you are in the mountains today be watching for:

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 75% of the way down from the top.  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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