Avalanche Advisory for Thursday, April 20, 2017

This advisory expires at Midnight.

Huntington and Tuckerman Ravines have LOW avalanche danger. Natural and human-triggered avalanches are unlikely. Generally safe avalanche conditions exist. The Little Headwall is now a waterfall with open holes and thin snow bridges above.

AVALANCHE PROBLEM: Loose wet sluffs may be a problem for those seeking out turns in the sloppy snow today but recent freeze/thaw cycles have reduced more significant avalanche concerns. The one outlier is always the areas around running waterfalls which sometimes spill water into the snowpack and release a deeper wet slab. It’s a good idea to keep that hazard in the back of your mind, particularly beneath the growing waterfall hole in the Lip/Headwall area.

WEATHER: Temperatures climbed above freezing in the Ravines yesterday which continued to melt the copious stockpile of snow that we have squirreled away over the winter, though a quarter inch or so of ice pellets made a contribution yesterday afternoon. There was 80” at the snow stake at Hermit Lake on April 1. As of yesterday morning, we were down to 57”. Temperatures will remain above freezing again today with fog, clouds and some more showers of mixed precipitation early and then again after 5pm. West winds in the 30-40 mph range will calm and shift southwest at 20-30 mph. Overall, a pretty gloomy day is on tap.

Be aware of the following hazards today:

  • Long sliding falls – Crampons are highly recommended in steep terrain. Snowshoes and microspikes are no substitute. Arresting a fall on an icy 30+ degree slope can be practically impossible, even with an ice axe. Any slip could potentially turn into a slide for life and could put you into a glide crack or waterfall hole.
  • Crevasses or glide cracks, moats and waterfall holes – Water flowing under the snow pack creates holes and thin spots in surface that are deep enough to injure or kill you. New snow can drift and obscure the openings. Glide cracks, our version of crevasses, form when the snowpack gradually creeps downhill. As the snow pulls away from a cliff, this creates a gap that could swallow a person. The glide cracks are becoming more widespread and a number of them are now big enough that someone could disappear into one. The waterfall hole in the Lip is growing each day and has a long history of acting in unpredictable ways.
  • Icefall: This hazard is unpredictable but above freezing temperatures certainly increase the risk of ice releasing from a cliff. Ice falls, rolls and slides with surprising speed at times. Don’t count on your ability to dodge this hazard. It is best to reduce your risk by reducing time spent beneath frozen waterfalls. As we move forward, remember that Lunch Rocks is in the bullseye of the massive ice in Sluice which makes hanging out there a high stakes game of roulette.

The Little Headwall is now more water than snow and is no longer recommended as a descent from The Bowl. The easiest and fastest descent is to hike down the Tuckerman Ravine Trail to Hermit Lake before skiing or riding. The Sherburne Ski Trail is melting fast and much of the trail close to Pinkham is mostly dirt and grass. In order to prevent erosion problems, please remove your skis and walk back to the Tuckerman Ravine trail from the rope placed across the trail. It is currently at crossover #3 but will likely move uphill by the weekend as warm temperatures at lower elevations melt the snow up the hill.

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 caretaker at Hermit Lake Shelters.

Posted  7:10 a.m., Thursday, April 20, 2017. A new advisory will be issued tomorrow.

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

2017-04-20