Avalanche Advisory for Wednesday, January 11, 2017

This advisory expires at midnight.

Huntington Ravine has CONSIDERABLE avalanche danger today. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are required.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger. Sluice, Lip, Center Bowl, and Chute have High avalanche danger. Natural avalanches are likely and human-triggered avalanches are very likely. Very dangerous avalanche conditions exist. Travel in this terrain is not recommended today. Lobster Claw, Right Gully, Left Gully, and Hillman’s Highway have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route-finding, and conservative decision-making are required.

AVALANCHE PROBLEM: Wind Slabs will form throughout the day. New snow last night with strong, shifting winds today will create large wind slab in all areas. These new slabs will see increasing loads throughout the day and with well-developed avalanche paths, they have the potential to run far. The terrain above Connection Cache in Tuckerman and the Fan in Huntington is avalanche terrain – don’t be lulled into a false sense of security. While there are areas that could be traveled in, with careful snowpack evaluation and cautious route-finding, good conservative decision making may lead to not traveling in avalanche terrain today.

WEATHER: Snow began to fall yesterday afternoon and continued through the night. This morning, snow totals range from 4.5” at the summit to 3.5” at Hermit Lake. During the hours of snowfall, winds remained from the south in the 60-80mph range. Winds will remain strong for the morning with gusts well above the century mark, shifting to the west. We may see an additional 1-3” of snow today as the front passes and winds decrease to 45-60mph. Temperatures will increase, surpassing the freezing mark during the night and reaching the mid-30s by daybreak tomorrow.

SNOWPACK: The current snowpack is comprised of several layers of wind slab. Snow that began yesterday afternoon fell on a varied surface; primarily firm edgeable wind slab that developed between Sunday night and Tuesday. These older wind slabs were fairly strong and it took a massive chunk of ice in the steepest terrain to initiate an avalanche below the headwall in Tuckerman Ravine. The give or take 4”of snow that fell last night came with strong south winds as well as increasing temperatures. As winds shift to the west this morning, we will see the cross-loading of slopes and significant new loading as snow from the west side of the mountain and the alpine fetch blows into our forecast zones. This morning, there were no signs of natural avalanche activity observed.  Shifting strong winds, increasing temperatures, significant new loading, and 4”+ of new snow over the last 12 hours are all red flags which are present today. Expect increasing danger through the day.

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 8:35a.m., Wednesday, January 11, 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

2017-01-11