Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
No rating
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

New snow and ramping winds will create very dangerous avalanche conditions in north, east, and south-facing terrain. These wind drifts will be destructive, large enough to bury multiple people, and could avalanche naturally. Traveling in avalanche terrain is not recommended.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–3

    Very large wind slabs will be forming on north, east, and south-facing terrain as northwest winds increase throughout the day. By midnight MWOBS recorded 4.4 inches of snow and by 6:00 AM Hermit Lake reported 7.87 inches of snow. Considering that snow, additional snow forecast through the day, and unconsolidated snow that is available for transport that has been observed on the west side, there is significant snow available to build wind slabs and this will create very dangerous avalanche conditions today. 

    Traveling in avalanche terrain is not recommended as natural avalanche activity is expected. There is no way to safely assess conditions given the size of potential avalanches and blowing snow will limit visibility. Wind slabs are most sensitive during their formation, and with significant snow and increasing winds they will be forming throughout the day.

Avalanche Discussion

The past few days there has been a large natural avalanche cycle that produced destructive avalanches, see observations from Hillmans and Tuckerman Ravine here. These natural slides have increased the path size and future slides have the potential to run further because of this cycle. While some of these wind slabs have avalanched, there are places in terrain that have not, like Gulf of Slides Main Gully, and these wind slabs are still in the process of settling. New wind slabs forming today could create enough stress to step down to these lingering wind slabs and produce very large and destructive avalanches. With conditions today there will be no way to easily assess what has and has not run as winds may scour debris, new snow will cover any evidence of crown lines, and new snow will bury remaining wind slabs. 

This past cycle saw consistent west winds at moderate speeds, today ramping northwest winds return. Observations from the public and forecasters confirm that there is dry and unconsolidated snow that remains on the west side, there have just not been winds strong enough to transport this snow yet. Today that changes and the size of very large avalanches and HIGH hazard forecast today is accounting for this snow.

A professional observation from Tuckerman Ravine yesterday shows the scale and changed snowscape of this very large, unsurvivable, and destructive natural avalanche. Skinning into the ravine terrain looked almost unrecognizable, with landmarks like Levy Rock and Connection Cache fully buried. Talking with other forecasters this seems like this may have been a 1~20 year event as no one could readily recall Connection Cache being buried by debris. If you have memories of this differently, please reach out as we would love to talk!

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