Avalanche Advisory for Monday, December 26, 2016

This advisory expires at Midnight tonight.

All forecast areas in Huntington Ravine have LOW avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

All forecast areas in Tuckerman Ravine have LOW avalanche danger. Natural and human-triggered avalanches are unlikely. The exceptions are Lobster Claw, Lower Snowfields and Little Headwall which are not rated due to a lack of snow.

Watch for unstable snow on isolated terrain features in both Ravines. Low danger does not mean no danger.

AVALANCHE PROBLEM: Stubborn wind slab will be the avalanche problem to concern yourself with today. High west winds the past two days repeatedly moved snow around in the terrain, scouring many areas and redepositing snow in others. In general, the snow took a beating as you would expect with gusts to 100 mph. Pockets of smooth but firm wind slab that escaped this pounding should hold your attention in the steepest terrain. While stubborn, these wind slabs could be triggered if loaded in the right spot. Assess and avoid large smooth pillows of snow whenever possible.

WEATHER: A scant .5” of snow fell early yesterday morning but otherwise no new snow was recorded in the past 24 hours. Sustained WNW winds in the 75-90 mph range on Christmas Eve moderated by mid-day yesterday. This morning the wind has died completely at lower elevations with 20 mph west winds on the summit. Winds will increase today to 50-70 mph by nightfall as low pressure moves in. Precipitation will start out as freezing rain after dark followed by rain before turning back to snow by morning.

SNOWPACK: Our snowpack has grown more slowly in the past week than it did earlier in the month when four distinct and widespread avalanche cycle quickly filled in our avalanche paths with debris. The majority of the 67” of snow recorded so far this December fell during the first half of the month. Since that time we received one rain event followed by small amounts of snow that built the stiff wind slabs that currently pepper our terrain. These upper wind slabs, while generally discontinuous and not exceptionally weak, should hold your attention in the steepest terrain. Plenty of old surface is still providing safe travel options that should allow you to avoid suspected unstable areas. The refrozen crust that dominates is hard enough to warrant crampons as terrain steepens but is breakable over faceted snow off trail and in the bushes so expect post-holing conditions in less frequently travelled terrain. Steep terrain is generally very firm and as such will resist efforts at self-arrest.

The Lion Head Winter Route is open and the most direct route to the summit. The Tuckerman Ravine Trail bridge is completed enough to allow traffic again so you can avoid the detour. Please be careful of construction debris near crossover 7 on the Sherburne Trail and watch out for machine traffic since the Tuckerman Ravine Trail is still not really passable for snow machines. Thanks for your continued patience!

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 8:20 a.m., Monday, December 26, 2016. A new advisory will be issued tomorrow.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2716

2016-12-26