Bollettino valanghe

Presidential Range

Mount Washington Avalanche Center
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Pericolo valanghe

Mon
Alta quota
1 · Debole
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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In sintesi

You could trigger an avalanche in steep terrain where the wind has formed deep drifts of snow. Watch out for softer snow drifts where your boots or skis are easily punching through. Long cracks in the snow, hollow or drum-like sounds or feeling, and smooth or rounded snow drifts are all signs of a potentially dangerous avalanche problem.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    What and where is it:Watch for wind slabs formed from the 5.5 inches of snow over the past 3 days. Strong west winds have likely scoured exposed terrain and limited slab development at upper elevations. Below ridgelines, at middle elevations, you may find larger, more cohesive slabs in wind-sheltered terrain, especially in gullies, below rollovers, and other terrain features that collect drifting snow.Late tonight, watch for new snow accumulating in steep terrain. By the morning hours, this will likely be a new avalanche problem to consider. New snow will have the ability to hide visual cues of older wind slabs. An avalanche in new snow could have the ability to step down into deeper weak layers in the snowpack and create a bigger avalanche. 

    How can you recognize it: Look for fresh, smooth, rounded drifts, and check how the new snow is bonding to the older, firm snow surface by digging down into the snowpack. Shooting cracks, a hollow or drum-like feel, and drifts deeper than your boot tops are strong clues you’re on a potentially dangerous wind slab.How can you manage it: Assess steep slopes before you commit to them. Use smart travel techniques that minimize your exposure to areas of wind slab and the runout zones below. Traveling on hard, supportable snow surfaces can reduce the risk of triggering a wind slab avalanche today.

Avalanche Discussion

The overall possibility of triggering a recent wind slab in steep, easterly ravines is decreasing with time - but do not completely ignore this potential. Extremely cold temperatures may have preserved mid-slab weak layers, limiting settlement and bonding. Stay vigilant by making routine snowpack observations throughout your tour, digging down into the snowpack to assess any potential layers of concern. Deeper in the snowpack, between 3000 and 5000 feet in elevation, a persistent weak layer consisting of the January 10th melt-freeze crust with weak or faceted snow above still exists. In most of the biggest avalanche terrain, like in Tuckerman Ravine and Gulf of Slides, this layer is buried over 3 feet deep by dense, supportable snow. In these areas, the ability for a person to trigger an avalanche on this layer is very unlikely, but if you did, the avalanche could be large with hard debris.More likely, is small avalanche activity in soft, incoming snow late this afternoon and tonight. As snow starts to accumulate, expect avalanche danger to increase. Also keep in mind that new snow will hide any visual evidence of previous wind slabs. Consider this as the avalanche situation becomes increasingly complex and dangerous leading into tomorrow and Tuesday. With weather models still changing by the hour, look for our updated avalanche forecast tomorrow and keep your mountain objectives flexible to account for this upcoming dynamic period.OBSERVATIONS: Please consider submitting an observation on our website or in the new Avy phone app 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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