Avalanche Advisory for Monday, February 22, 2016

Tuckerman and Huntington Ravine have MODERATE avalanche danger. Natural avalanches are unlikely but human-triggered avalanches are possible. Evaluate snow and terrain carefully.

 AVALANCHE PROBLEM: Wind slab is the primary avalanche problem today. Widespread, smooth slabs reach from wall to wall in most gullies in both Ravines this morning. These slabs have a layer of lower density snow beneath them and will create challenging conditions in which to apply safe travel skills, careful terrain management as well as ongoing, critical assessment of slope stability. Expect the wind slabs to vary in thickness with the consequences of triggering any size avalanche particularly dangerous due to the ice crust beneath and the many rocks and ice cliffs that remain exposed.

WEATHER:  We received around 9” (22cm) of new snow in the past 3 days with only 1” (2.5cm) falling yesterday. Wind speeds ramp up for a brief period but no real scouring occurred. Today’s weather should be clear and cold with summit temperatures around 0F. Currently, brilliant sunshine and calm winds at Ravine level are providing a nice break from the last several days of murky gray but unseasonably warm weather. This time of year the increased daylight and angle of the sun has the possibility of rapid warming on the list of concerns but we won’t likely get there today. Expect continued cold today as high pressure settles in with NW winds in the 30-45mph range.

SNOWPACK: Only a few areas of the Feb 17th melt freeze crust are showing in the Ravines. The avalanche debris showing in Huntington Ravine is from wet loose activity last Thursday. Higher in the start zones a crown line in Chute from the same cycle is now buried as is the older crown line through Center Bowl and the Lip. The 8” (20cm) of new snow coupled with southwest winds on Friday and Saturday really filled in upper sections of Hillman’s Highway and Left Gully, though both are still well behind a normal snow level. Winds shifted from the south to the west, crossloading or just plain loading much of the terrain, leaving very little of the textured sastrugi snow that we see following high winds. South facing gullies in Huntington indicate that some scouring may have occurred early in the 8” storm cycle but subsequent cross loading has built slabs in the mid-sections.

The Lion Head Winter Route is open and the recommended east-side route to the summit that avoids avalanche terrain. The John Sherburne Ski Trail is in a typical mid-winter state with packed snow and some bare patches of ice that become a more significant problem the lower you go on the mountain. Recent snow was highly elevation dependent with some rain falling at Pinkham Notch so expect icier trail conditions down low.

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 8:20a.m., February 22, 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

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