We are no longer issuing daily avalanche advisories this season for Tuckerman Ravine, however, we will continue to provide snowpack and weather information when conditions change. Avalanches, falling rocks and ice, undermined snow, large glide cracks, and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains. We are no longer monitoring conditions in Huntington Ravine, but hazards will persist until all the snow and ice disappears.
High pressure will build into the region from Canada on Monday, keeping clear conditions until late in the week. Temperatures during the days will reach into the 40sF and nighttime lows will drop into the 30sF. Low pressure will move into the area late in the week bringing unsettled weather. Our springtime isothermal snowpack has generally reduced avalanche concerns to sluff management in steep terrain.
The following hazards have all caused fatalities and should factor into your decision-making process:
- Icefall: All visible ice will fall down at some point, often in large chunks that travel at high rates of speed. The most hazardous locations are in the center and looker’s right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur. Speed is safety when passing under any ice flow.
- Glide Cracks and Waterfall Holes: As the snowpack gradually gives way to gravity, it pulls away from cliffs and leaves cracks that are most visible in extreme terrain, particularly the Lip. These glide cracks will grow larger and increase in number. The large waterfall hole in the Lip has spawned large and destructive wet slab avalanches in the past during times of heavy rain.
- Undermined Snow: In addition to melting on the surface, the snowpack is eroded by running water beneath. This creates thin snow bridges that will collapse and are most prevalent in areas that have streams and at the tops of south-facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.
- Long, Sliding Falls: Spring corn snow comes from the melt/freeze cycles on warm days and cold nights. The freeze portion of this cycle can turn a gully full of corn snow into an icy slope remarkably fast, possibly turning what would be a great ski descent into a down climb that requires crampons and an ice axe.
The Winter Lion Head Route is still open due to the amount of snow on the Summer Trail. The Sherburne Ski Trail is open down to crossover #7, allowing about ¾ mile of skiing below Hermit Lake. Please respect the rope, cross over to the Tuckerman Ravine Trail, and hike down to Pinkham.
• Safe travel in avalanche terrain requires training and experience. This bulletin 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, the Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.
• Posted 2:30pm., Sunday, May 6, 2018. A new bulletin will be issued when conditions warrant.
Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856