We are no longer issuing daily avalanche advisories this season for Tuckerman and Huntington Ravine. However, we will continue to provide snowpack and weather information for these areas when conditions change drastically and in time to help you make, or change, weekend plans. 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. Spring weather brings about rapid changes to the snowpack and presents objective hazards accordingly. Remember to ski, climb, or hike the snowpack and weather conditions that exist and not a date on the calendar!
This past weekend was a perfect reminder of how fickle spring weather can be. Saturday’s crowds were delighted by sunshine and abundant spring snow while those who ventured up to the Ravines on Sunday found rain and sleet at mid elevations and 11.1” of new snow on the summit. With light and variable winds, this snow likely blanketed higher terrain. Lingering instability in the atmosphere Monday will keep temperatures around the freezing mark for another 1-3” of snow and sleet on the summit. Building high pressure on Tuesday will create a clearing trend into Wednesday along with increasing wind speeds and temperatures. New snow from Sunday will experience rapid warming over the forecast period. Those venturing into avalanche terrain should be aware of the potential for wet avalanches. While wet-loose sluffs may be slow moving, this sort of “push avalanche” can easily take a skier over a cliff or into a glide crack. New snow will also cover developing holes in the snowpack, making safe navigation that much more difficult.
Remember to keep the following hazards in mind as you plan your route:
- Icefall: Over the years many people have been severely injured or killed by falling ice in Tuckerman. The most hazardous locations are in the center and 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. Avoid spending time in the areas listed above and underneath any ice flows.
- Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves gaps. These gaps are the horizontal cracks that will soon appear in the steep terrain, most noticeably in the Lip. These are deep enough to cause fatal injuries, especially around the main waterfall. This waterfall hole in the Lip is a unique hazard. In addition to creating a fall hazard, the flowing water has spawned large and destructive wet slab avalanches in the past.
- Undermined snow: Meltwater flowing under the snowpack melts away the snow above, creating thin bridges of snow that can collapse. These are beginning to emerge at the tops of gullies (particularly on south-facing slopes) and in areas that have streams running, like the brook feeding the Little Headwall. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard. Breaking through weak snow into one of the larger water courses could be fatal if you become trapped.
- Long, sliding falls: Part of what makes spring skiing so great is the melt/freeze cycle that creates stable, firm corn snow. The cycle begins when the snowpack freezes at night or in the afternoon shade on cooler days. This refreeze creates a hard surface on which it is nearly impossible to arrest a fall with skis or an ice axe. Refrozen snow can cause trouble for those looking to get “just one more run” at the end of the day.
While icy, the Winter Lion Head Route remains the preferred option for summit hikers due to the fall hazard at the traverse near treeline on the summer trail. Those who are summit bound should be on the lookout for this to change by the weekend. The lower section of the Sherburne Ski Trail is closed around the switchbacks of the Tuckerman Ravine trail, about ½ mile from the parking lot. Expect this closure to move up in elevation as temperatures skyrocket this week. In order to reduce erosion on the ski trail, please walk over to the Tuckerman Ravine Trail and hike the rest of the way to Pinkham Notch.
• 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, the Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.
• Posted 7:40 a.m., Monday, April 30, 2018. A new advisory will be issued when conditions warrant.
Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-