Lawinenlagebericht

Presidential Range

Mount Washington Avalanche Center
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Lawinengefahr

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

Kernpunkte

Triggering a large avalanche of wind drifted snow 1- 3 feet thick is possible today, especially in east-facing ravines such as Tuckerman Ravine and Gulf of Slides. An avalanche will be more likely where the wind has formed drifts from the recent snow. Identify areas of concern by looking for a smooth, pillow-like snow surface. You can reduce your risk of triggering an avalanche by avoiding steep slopes loaded with wind drifted snow.

Lawinenprobleme

  • Wind Slabs

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

    Large, human-triggered wind slab avalanches are possible today in wind-sheltered areas on steep terrain features that face north, east, and south. The most likely trigger points are in the steepest sections of avalanche paths where smooth, softer snow is present. 

    Multiple crust layers below in the top 1 - 3 feet of the snowpack have the potential to act as a slick bed surface for this avalanche problem. Dig down to assess the stability of these interfaces while understanding that variability exists across the terrain. Practice safe travel techniques and good terrain management by traveling one-at-a-time in avalanche terrain and reduce overhead hazard with careful, strategic route planning.

Avalanche Discussion

In addition to the thicker slabs that are talked about in the wind slab description, there is a potential for new wind slab development if we see a higher snow total today of 2 or 3 inches. This light density snow could create thin, reactive slabs on the snowpack surface if the winds are lighter, or it could be blown past avalanche terrain and not a concern if the winds are stronger. Any new wind slab development should be easy to assess and small. The greater concern today are thicker wind slabs that are less reactive, but carry big consequences. Look for multiple sub-surface crust layers and some subtle mid-slab density changes if you are interested in investigating this problem further. 

The development of a persistent weak layer adjacent to a melt/freeze crust layer that likely formed on January 13 contains weak faceted grains trapped between two harder crust layers. This poor snowpack structure, which has been observed in several areas, has not been producing avalanches. We will be watching for continued degradation of the crust and facet development which could eventually turn this layer of concern into an avalanche problem. The race will be between high Mount Washington winds to create an upper snowpack that effectively bridges loads over this layer and next week’s very cold temperatures, which could drive snowpack weakening. 

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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