Avalanche Advisory for Wednesday, January 4, 2017

This advisory expires at midnight.

Huntington Ravine has MODERATE avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully.
Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Lobster Claw, Right Gully, Left Gully and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features.
AVALANCHE PROBLEM: Today’s avalanche problems are Storm Slab this morning with the potential for the development of Wind Slabs as the day progresses. Expect avalanche danger to increase as the next system moves in with increasing winds and more snow on the way today with the potential of up to 6” of new snow through the night. Expect new wind slabs to form in the deposition zones of west winds, especially in steeper terrain and under ice bulges such as the Headwall region in Tuckerman and the bottoms of Central, Pinnacle, and Odell. Visibility will be challenging at times today with whiteout conditions, making safe travel more difficult.
WEATHER: Yesterday was true mixed bag of precipitation on the mountain. The Cutler River Drainage received periods of snow, ice pellets, rain, and freezing drizzle. Winds started out of the S, shifted to the SE, and then swung all the way to W, remaining in the 50 mph range. Overnight, winds decreased to 35mph and delivered 5” of snow at Hermit Lake. Today, upslope snow will bring another 1-3” to the mountain and winds will increase to 70mph by nightfall. Winds tonight will remain from the west and continue increasing to 90mph, along with the possibility of another 1-3”.
SNOWPACK: Prior to yesterday, our snowpack consisted largely of a variety of wind slabs along with scoured old surface. These surfaces were bonding quite well to each other. The wind slabs tend to have pencil hardness low transitioning to one finger hardness higher in the slab, creating a right-side up slab. Yesterday, snow, mixed with ice pellets, fell to start the precipitation which then transitioned to more of a frozen drizzle/rain mix into the night. This created a thin crust on top of the current snow. With winds increasing today and the potential for up to 3” of snow today and up to another 3” tonight, there is potential for the snowpack to become upside down. Travel in avalanche terrain today will require constant reevaluation of the snow and weather, realizing that conditions are trending toward a less stable snowpack as the day progresses.
The Lion Head Winter Route is open and the most direct route to the summit from the east side of the mountain. Please be on the lookout for machine traffic on the Sherburne as we remove construction debris over the coming week.

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 8:25a.m., Wednesday, January 4, 2017. A new advisory will be issued tomorrow.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2713

2017-1-4