Bulletin d’avalanche

Presidential Range

Mount Washington Avalanche Center
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Danger d’avalanche

Tue
Alpin
1 · Faible
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering an avalanche in wind-drifted snow is possible at middle and upper elevations. Watch out for areas of smooth, wind-drifted snow on wind-protected slopes that could avalanche from the weight of a single person. Traveling on the hard, textured old snow surface instead of smooth, deeper snow drifts can help you avoid this avalanche problem.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    Expect to find wind slabs at middle and upper elevations on northeast through south aspects and in wind-protected terrain features. Slab depth will be variable between 1 and 3 feet thick. These slabs have formed on top of a slick melt/freeze crust which may make them more sensitive to the weight of a single person. In many areas, wind has scoured snow away and exposed the firm and generally stable old snow surface.

    Watch for boot penetration in new snow that goes past your ankles and softer snow that has strong-over-weak characteristics. This is a sign you may have found a sensitive new wind slab. Traveling on hard, textured old snow surfaces is one way to navigate around this avalanche problem.

Avalanche Discussion

After about 4.3 inches of new light-density snow recorded at Hermit Lake over the past 48 hours, combined with a significant prevailing west wind, new wind slabs resting on a slick old snow surface have become the primary stability concern. Observations from yesterday supported reactive sensitivity of new wind slabs and a resistance to bonding to the old snow surface, which is a slick melt/freeze crust in many areas. With continued wind and increased time, new wind slabs will trend towards stubborn reactivity, however, persistent cold temperatures may slow down this process. 

Safe travel today will require making slope-specific assessments to account for the large variability in conditions and stability. This also applies to specific terrain features. The snow at the bottom of a gully may not be representative of the snow that is at the top the same feature. Traveling on the old snow surface to avoid the avalanche problem carries a separate risk of sliding falls where it may be impossible to self-arrest. Careful route planning that considers both of these hazards is important today but may be difficult due to poor visibility. 

The Lion Head Summer Trail is CLOSED due to increased avalanche hazard. The Lion Head Winter Route is OPEN and the most direct route to the Mount Washington Summit from Pinkham Notch. 

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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