Avalanche forecast

Presidential Range

Mount Washington Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Avalanches are possible on steep, east and south-facing snow slopes above 3000 feet in elevation. Watch out for quick changes in snow hardness, cracking, or recent avalanches, which are signs of unstable snow. Sound decision making, knowledge, and safe travel techniques are necessary for safe travel in avalanche terrain today.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    Wind slabs varying in depths from 1 - 6 feet deep can be found in steep, alpine terrain on easterly and southeasterly aspects. Expect these slabs to react stubbornly to potential triggers. This avalanche problem could produce large avalanches that are D2 or D2.5 in size and slide deep into runout paths. Though slabs are thick and firm in some areas, finding a thin spot near the flanks of a slab will make triggering an avalanche easier to do. Knowing where thin spots are from a distance can be impossible.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    A shallow snowpack and very cold temperatures has driven the development of weak faceted crystals of snow at lower elevations in and outside of our forecast area. The addition of a wind slab (which may have developed in isolated areas) may make this problem more sensitive to a trigger. Steep snow slopes on all aspects at lower elevations may fail from the added weight of a skier or climber. Red flags for this problem may include an audible whumpfing you can hear and feel, and shooting cracks in the snowpack around you. Also keep in mind the consequences of even a small avalanche if you are climbing or skiing in steep technical terrain.

Avalanche Discussion

Good visibility yesterday confirmed widespread natural avalanche activity from February 5th on easterly and southeasterly aspects in mid and upper elevations. This includes most of the slide paths in Tuckerman Ravine, the more developed paths in Gulf of Slides, the Ball Crag/Alpine Garden area, and in Huntington Ravine. Especially in avalanche runout zones, alpine terrain has filled in significantly more with snow after this recent storm and avalanche cycle. This means that starting zones have the ability to hold more snow and produce larger avalanches that can travel farther and faster. Keep this in mind when travelling under slopes, and especially when other people are in the terrain above you. 

Even though evidence of avalanche activity can be seen throughout the terrain, it is not necessarily an indication of a stable or safe slope. Many of the areas where a crown line is still visible have been re-loaded by wind-transported snow and could produce another avalanche on the same bed surface. Additionally, remember that a wind slab in the starting zone of an avalanche path is likely going to act differently than the snow in other locations. This means that instability test results or snowpit profiles elsewhere are likely not representative of the snow and avalanche problem in the start zones.  

We’ve been tracking development of facets at elevations below 3000 feet for the last few weeks. The facets exist, but generally have not been an avalanche problem due the shallow snow pack. Recent observations (Wildcat, Grafton Notch, Great Glen) show that the 12 inches of new snow have not only added stress to the weak snowpack, it also created the potential to be an avalanche problem with the increased volume of snow. Keep this in mind when traveling on slopes steeper than 30 degrees at lower elevations. However, if conditions are such that they are not producing avalanches then they may be best thought of as dormant. We’ll watch this over the next few days to see if this weak snow structure is capable of producing an avalanche, if not we’ll likely remove Persistent Slab as an avalanche problem.

1-3 inches of new snow is forcast to fall overnight tonight with the potential for some mixed precipitation as well.  Overnight, small surface slabs could develop especially on northerly aspects which should be kept in mind if traveling after dark and when today's forecast expires. 

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

Please help us and your fellow skiers, riders, and climbers by submitting any pertinent or interesting observations to our website. 

Regions covered