Avalanche Advisory for Friday, March 23, 2018


Huntington and Tuckerman Ravine have LOW avalanche danger today. Generally safe avalanche conditions exist. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEM: Wind slab is the avalanche problem today. It is unlikely that a human could trigger the current wind slab in our terrain due to its firm and supportive nature. As the slab itself has a high degree of tensile strength, an avalanche would be large, giving travelers in avalanche terrain a classic low probability, high consequence situation. Small areas of softer slab exist that are providing the isolated pockets of less stable snow. The surface of our snowpack is largely smooth, providing quality skiing, but also the ideal surface for a long, sliding fall. Losing a ski edge or catching a crampon point in steep terrain today will likely have dire consequences. With the possibility of 1” of snow today, dry loose sluffing in extreme terrain should be on your radar as wind speeds are forecast to be on the low side.

WEATHER: The fourth Nor’easter of March was less impressive than the others, bringing overcast skies and mild temperatures. We saw no new snow yesterday (or any of the previous four days), recorded a high temperature of 19F and a low of 9F on the Summit, and saw NE wind shift to the NW and stay in the 30-50mph range. Today will be somewhat similar, though summit fog should move in this afternoon. Wind will drift between N and NW and stay in the 25-40mph with periods of lower speeds. Up to an inch of snow may materialize today, though this should be hold off until later in the day if at all.

SNOWPACK: Significant snowfall in early-March followed by recent strong wind has left widespread, firm wind slab in most of avalanche terrain. This wind slab is supportive and is providing excellent climbing and good skiing provided you bring crampons and stay on your edges. Softer pockets of snow exist under terrain features and near the edges of gullies, particularly in the trees. Off trail travel that is not in a gully may require serious post-holing.

The Harvard Cabin is open this weekend.

Please Remember:
• Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
• Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast. For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or Harvard Cabin.
• Posted 7:50 a.m., Friday, March 23, 2018. A new advisory will be issued tomorrow.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856