Avalanche Advisory for Thursday, April 7, 2016

Tuckerman Ravine has MODERATE avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible in all forecast areas. Evaluate snow and terrain carefully. Lobster Claw, Little Headwall and Lower Snowfields are not posted due to lack of snow.

Huntington Ravine is under a General Bulletin. You will need to do your own snow stability assessments when traveling in avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

AVALANCHE PROBLEM: Several potential avalanches problems are in the mix today. This morning, there is a Low danger in the pockets of wind slab which developed on Tuesday. These are scattered in the steepest areas sheltered from a west wind like beneath the ice in the Lip and Center Bowl and in the mid sections of Chute and Left. Later today, it will become more possible to trigger these slabs as temperatures warm and rain falls. More wind slabs may develop on a south wind, this morning through mid-day, if new snowfall persists before changing over to rain. Anticipate the small pockets of older wind slab and any newer wind slabs developing today to become a wet slab/wet loose problem late in the day and overnight as heavy rain develops.

WEATHER: Mountain weather is warming to more seasonable temperatures just long enough for 1-2” of rain to fall today through the overnight. Some new snow and sleet will fall prior to this changeover, though with 4300’ temperatures already at 31.7F at 7:10am, it seems as though the period of snow and mixed precipitation will be short-lived and perhaps occur only at the very highest elevations above our avalanche terrain. Expect a return to winter-like weather tomorrow with upslope snow showers and temperatures falling through the day, ultimately bottoming out in the single digits Friday night. Southerly winds, in the 40-50mph range to start, will shift west later today or this evening and ramp up to the 55-75mph range on the summit. Overall, expect an unpleasant brush with hypothermia if you head into the hills today.

Heavy rain will advance the spring hazards of undermined snow, waterfall blowouts and icefall until cold temperatures return tomorrow. In addition to treacherous wall-to-wall ice as you gain elevation on the Tuckerman Ravine and other trails, be aware of the following hazards and more today and through the weekend:

  • Long sliding falls – Crampons are highly recommended in steep terrain. Snowshoes and microspikes are no substitute. Expect a variable snowpack due to rain falling on a mostly firm surface with little boot penetration. Arresting a fall on an icy 30+ degree slope can be practically impossible, even with an ice axe. Refrozen snow and this sliding fall hazard will return with a vengeance after today’s warm
  • Crevasses, moats and waterfall holes – Warm 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.
  • Falling ice – The best thing you can do is reduce your exposure by limiting the time you spend downslope from frozen waterfalls. Falling ice chunks can move with surprising speed and follow unpredictable trajectories. Colder temperatures following this warm up will reduce the likelihood of this hazard.

The Sherburne Ski Trail is now closed at #7, allowing about 2/3 mile of skiing from Hermit Lake. Expect exposed ice with new snow. The Harvard Cabin is closed for the season. The only camping permitted in the Cutler River Drainage on the east side of the mountain will be at Hermit Lake Shelters.

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.
  • Posted 8:00 a.m., Thursday, April 7, 2016. A new advisory will be issued tomorrow.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2716