Avalanche Advisory for Sunday, January 25, 2015

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman Ravine and Huntington Ravine have CONSIDERABLE avalanche danger. Dangerous avalanche conditions exist. Natural avalanches are possible and human triggered avalanches are likely. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. The only exception to this is the Little Headwall in Tuckerman which has Moderate danger. Natural avalanches are unlikely and human triggered avalanches are possible in this forecast area.

AVALANCHE PROBLEM: Wind slab will be developing today, causing avalanche danger to be on the rise in all forecast areas. Some locations will be directly loaded from blowing snow being deposited on strongly sheltered slopes. The areas of greatest concern include the Sluice, Lip, and Center Bowl in Tuckerman as well as Central and Pinnacle Gullies of Huntington. Other adjacent locations will also have new slab development, and although not quite as quickly, the avalanche danger will rise in these areas to the Considerable level.

WEATHER: Yesterday evening Mt. Washington picked up some more new snow totaling just less than 3” (7.5cm) by 6am. Additional snow will continue through this morning. When it’s all said and done, 4-6” of new snow will be available for 65-85mph (105-139kph) NW winds to pick up and deliver to the eastern-facing ravines. You can expect falling temperatures through today along with the possibility of clearing out of the fog later. Until then, visibility will be quite poor due to fog and blowing snow.

SNOWPACK: Your primary focus on the snowpack today should be on the upper layer of slab that is developing. Some deeper issues may be of interest to serious snow geeks, but from the recreational perspective you can keep your attention at the surface and in the air above. Winds at 65-85mph have the capacity to pick up and move snow that has fallen far away from the ravines. Even if this morning’s forecasted 2-4” comes in at the lower end, we expect all areas to be loaded to a point where we have concerns of naturally triggered avalanches. If we do get the upper end of forecasted snowfall, in some locations we might be moving from naturally triggered avalanches being “possible” toward “likely.” Ultimately, today you should know that there are concerns about stability today, particularly with regards to human triggered avalanches if people are out in the avalanche start zones.

If you’re expecting boot-deep powder on the Sherburne, you’ll have a disappointing day. There may be drifts where it’s gotten that deep, but from Hermit Lake down to Pinkham there is less new snow that up above treeline.

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 the Harvard Cabin.
  • Posted 8:20 a.m. January 25, 2015. A new advisory will be issued tomorrow.

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