Lawinenlagebericht

Presidential Range

Mount Washington Avalanche Center
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Lawinengefahr

Fri
Hochgebirge
1 · Gering
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Veraltet — dieser Lagebericht ist 3 years ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

You could trigger an avalanche on areas of wind drifted snow at middle elevations in steep east-facing and south-facing slopes. To avoid this avalanche problem, travel on the hard, wind-scoured snow surfaces.

Lawinenprobleme

  • Wind Slabs

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

    Strong and extreme northwest and west winds have transported new snow to easterly and southern aspects across the terrain. These slabs are likely to be firm and stubborn to propagate, but sustained cold temperatures may harbor some lingering instabilities. In isolated areas, some terrain may have sheltered snow that may be more sensitive to being triggered. In areas where the snow is firm and wind textured, triggering an avalanche will be unlikely.

    If forecasted snow totals today are met, pay attention to new snow loading through the day and blowing snow on ridgelines. The new wind slabs will be thin, bright white, and easily avoided. With decreasing winds through the day, these new slabs may be softer and more sensitive. Hand shears to evaluate the interface of the new snow and old snow will help to understand sensitivity. Using a ski pole to measure depth will also help to understand the size and distribution of the current wind slabs in terrain.

    The areas of concern may be lower in gullies and steep slopes than expected as these high winds will have pushed the snow down and scoured start zones. Look for softer, smoother snow and evaluate that carefully. Visual observations of terrain will be critical today to evaluate where the wind slabs are and what they look like. Digging down to the interface of the old snow beneath it will also give you an idea of the sensitivity of this new snow.

Avalanche Discussion

Forecasters spent the morning discussing increasing stability in the current snowpack that supports the decreasing avalanche hazard we have today. The summit recorded over 30 hours of west and northwest winds that averaged 65 mph and accumulated over 5 inches of light, low density snow. With winds of these speeds and snow this light you should expect to find a firm, wind-scoured surface that will stretch into start zones at the tops of gullies near ridgelines in ravines. Because of these high winds, we dropped the wind slab problem from upper elevations. 

We also narrowed in the compass rose for where you will find the wind slab problem and removed north. Northern aspects accounted for the southern winds on the January 13th wind slabs. Lack of reactivity from field observations, natural avalanches, and skier traffic support the stabilizing trend of this previous wind slab problem. We believe the likelihood of this happening is unlikely, but that this would be a low probability but high consequence event as the size of this avalanche would be large. This extended period of cold temperatures may have preserved some instabilities within the snow, but these will be isolated and hard to trigger. Assess northern slopes carefully and consider the consequences of exposure like rocks or trees below you.

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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