Avalanche Advisory for Sunday, January 29, 2017

This advisory expires at Midnight.

Huntington and Tuckerman Ravine have MODERATE avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully to identify features of concern. The only exception to this rating is the Lower Snowfields and Little Headwall which have LOW avalanche danger. Natural and human-triggered avalanches are unlikely there. Open water and water ice remain exposed in the Little Headwall and the creek above.

AVALANCHE PROBLEM: Winds that created the wind slab avalanche problem over the past couple of days finally died down yesterday afternoon. These wind slabs along with newer, softer wind slabs should remain on your radar as you move into steep terrain today. The high velocity of the winds over the past several days has most likely created a wide mix a stiffness to these slabs, with the majority of them most likely being fairly stubborn in most areas. The northern gullys in both Ravines, while still having a moderate danger rating, are probably more scoured than loaded but new wind slabs will develop today. East facing areas served as a deposition zone for the snow which fell over the past few days and most likely went through a natural avalanche cycle during that time. Softer and smaller wind slabs are also in the mix due to the inch of snow that fell last night plus another inch or two falling today. These slabs will be much more sensitive to human-triggering and could result in a fairly significant avalanche if we receive the upper end of the forecast snow fall.

WEATHER: Just an inch of snow fell on the summit overnight however another 11” was recorded there since Thursday. In addition to the steady localized, upslope snowfall over the past several days, the main weather factor driving our avalanche problem is the continuously high winds that blew since Thursday night. The wind blew in the 70-100 mph range during that period from the west with a few hours from the WNW.  The past 12 hours has finally brought a steady decline in wind speed. Expect moderate winds today in the 30-45 mph range with lingering fog and snow showers bringing another inch or two of accumulation. Temperatures will be around 5F on the summit.

SNOWPACK: The icy crust created on Tuesday and Wednesday by sleet transitioning to rain is now well buried in wind sheltered terrain. Limited field observations due to elevated avalanche danger and low visibility tempers our ability to rate any forecast area low, but it is likely that North, Damnation and Yale and to a lesser degree, Lobster Claw and Right Gully were predominately scoured down to that old surface with pockets of wind slab in places. Hard, stubborn wind slabs will be possible to trigger in certain locations even though they may appear very firm. Ease into the terrain today and reduce you exposure to wind slabs. Dry-loose avalanches could become an easily manageable issue in steep terrain if the upper end of the forecast pans out.

The Lion Head Winter Route is open and the most direct route to the summit from the east. Please be careful of bridge construction debris near crossover 7 on the Sherburne Trail when skiing or riding.

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  7:30 a.m., Sunday, January 29, 2017. A new advisory will be issued tomorrow.

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

2017-01-29