Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
3 · Marcato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Wind loading this morning indicates drifting snow in east facing terrain. 1 to 4 inches of snow and strong westerly winds will build new slabs of wind-drifted snow in sheltered terrain. Eastern aspects in the middle elevations will have the largest and most sensitive concerning slabs. Have an awareness of the avalanche problem and where it exists as afternoon snow arrives with increasing winds.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    Wind loading this morning indicates windslabs building in east facing terrain.This afternoon we are expected to gain 1 to 4 inches of new snow and strong westerly winds. Cold atmospheric temperatures will likely make this snow less dense than what we are used to seeing in the east. Low density snow is easily broken down by wind and transported farther down slopes to areas where the wind is nil. In most circumstances snowflakes that get broken down into smaller pieces tend to pack more densely than larger flakes with more surface area. This can translate into slabs becoming quicker to firm and that could increase their sensitivity to triggering. Similar to yesterday's conditions, we can expect to see drifted slabs lower on the slopes and scoured surfaces in the starting zones.  

Avalanche Discussion

Friday's storm added around 7 inches of new snow to the mountains with strong gusting winds. Westerly winds helped to erode the newly fallen snow from the upper snowfields  and deposited it on middle elevation eastern aspects. The low density snow was easily degraded and transported to less exposed areas. Surprisingly many of the slabs we found in Tuckerman Ravine were less dense and about Fist hardness.

A combination of slick bed-surfaces, very light density snow, and an overnight cycle of Loose Dry avalanches helped promote safer skiing conditions during the afternoon. From afar it was difficult to discern that we had natural avalanches overnight until we climbed higher in the terrain and recognized the patterns. Some northeast through east aspects were primarily devoid of wind slabs, instead a firm and textured surface was found with minimal boot penetration. While more southeast and south aspects held soft dry snow without much wind affect, such as Right Gully. Slabs here were found to be around 1 foot thick, adhered well to the bed-surface, and slightly more than fist hardness.

There is much variability across the range and it is possible to find slabs on steep terrain ready for a human trigger. This will become more likely with afternoon snow and increasing winds from the west. Getting an early morning start today will benefit you in a number of different ways including enjoying more moderate avalanche conditions.

Thanks to everyone for taking the time to submit observations of snow and avalanche conditions, both inside and outside our avalanche forecast area. Please keep them coming.

The Lion Head Summer Trail is now closed for the season due to avalanche risk. The Lion Head Winter Route is open.

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