Avalanche Advisory for Thursday, March 3, 2016

Tuckerman Ravine has Considerable and Moderate avalanche danger.  Sluice, Lip, Center Bowl, Chute, Left Gully and Hillman’s Highway have Considerable avalanche danger. Continued wind loading keeps the potential for natural avalanches in these locations possible with human-triggered avalanches likely. Lobster Claw and Right Gully have Moderate avalanche danger. Natural avalanches are unlikely but human-triggered avalanches are possible. Evaluate snow and terrain carefully.

Huntington Ravine has Moderate avalanche danger. Natural avalanche are unlikely but human-triggered avalanches are possible. Expect hazard to be at the higher end of the rating in southern gullies with a greater degree of scouring reducing size of slabs slightly in northern gullies.

AVALANCHE PROBLEM:  Wind slab built from new snow and high winds yesterday is our avalanche problem today. This new snow was dry to start with a period of damp snow before temperatures dropped and winds ramped up, shifted directions and began moving snow. This created a somewhat upside down snow pack with denser wind slab on top of these layers. Carefully monitor snow pack if you brave the frigid temperatures and travel in our forecast area today. Moderate rated areas could certainly be triggered today despite the firmness of the upper slab.

 WEATHER: The storm Tuesday night and Wednesday dropped around 8” of new snow above 3800’. Below this point, snow became heavy and wet with some rain mixed in at lower elevations. At higher elevation, the snow was dry and easily transported by high winds from the south at the start of the storm which ended blowing from the west in the 75-90 mph range. During the final six hours of west winds, 2-3 inches of snow fell. These higher wind speeds appear to have done a bit of scouring in northern gullies and some higher start zones. Winds will diminish some today but expect some continued loading early.

 SNOWPACK: Crown lines from avalanche activity in the Lip, across the Center Bowl and near the top of the upper left fork of Hillman’s are obvious this morning, along with signs of some scouring. That said, I would count on many wall-to-wall pockets, and larger areas, of wind slab still lurking in lee areas of the terrain with continued loading stressing the remaining slabs. Upper South Gully in Huntington stands out as an area of concern due to its increased expanse with similar aspects Tuckerman Ravine, like portions of Hillman’s, also harboring disconcertingly large and potentially unstable slabs. The snow associated with this storm was highly elevation dependent so expect drastic changes with elevation as well as aspect. Snow did not bond well with ice at lower elevations and it is likely that this new snow formed only a tenuous bond with those areas of melt freeze crust that were not covered with more textured hard wind slabs in our forecast areas. Lower Sherburne is crust over sugary snow on top of ice.

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 8:40am, March 3, 2016. A new advisory will be issued tomorrow.

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