This advisory expires tonight at 12:00 midnight.
Tuckerman Ravine has MODERATE and LOW avalanche danger today. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas of Tuckerman have Low avalanche danger. Natural and human triggered avalanches are unlikely. Unstable snow may exist in isolated terrain features.
Huntington Ravine has LOW avalanche danger today. Natural and human triggered avalanches are unlikely. Unstable snow may exist in isolated terrain features in these locations.
AVALANCHE PROBLEM: Wind Slabs are the primary issue today, although isolated across the terrain. High winds overnight maxing out at 115 mph have done an admirable job scouring many areas to the old hard rain crust from 2 days ago. Wind Slabs will be isolated across the Ravines to the most protected areas from W winds. Pockets beneath steeps bulges and terrain features are locations to look for these wind slab instabilities.
WEATHER: Very cold air and a tight pressure gradient have made the mountain rather inhospitable and unruly. The mercury fell down to -24F with a max wind velocity of 115mph. Although a little less surly, the current temperature of -15F with winds dropping from 75-90 this morning to 50-70 mph later, is still nasty and unforgiving. If venturing above treeline assure you have very good Arctic mountaineering clothing with a focus on your most vulnerable parts, the hands, feet and head.
SNOWPACK: The warm and rainy weather on Monday, with the Arctic freeze up that followed, have made conditions and weaknesses below this hard crust layer fairly moot. The few inches of new snow that fell since then have hung into some pockets creating thin hard slabs. If you come across new wind slabs they are young and potentially unstable due to their cold crystals and the icy bed surface they are sitting on. The main location in either Ravine to find new slabs will be cross Tuckerman’s Center Bowl and Lip. Be suspicious. But generally, screaming winds have scoured most forecast areas down to the icy crust from Monday night. As winds die today and the possibility of additional snow showers, anticipate the possibility of new thin slabs to develop. If this occurs I would suspect it is unlikely the problem will be anything more than isolated.
The very hard slick surfaces that exist and a wind that can knock you off your feet will make falling in steep terrain is a real concern. Mountaineering experience in these conditions and the ability to execute an immediate self-arrest with your ice ax is essential. Once moving not even the famous mountaineer Reinhold Messner with a lifetime of experience could stop on this surface.
-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 830 a.m. Wednesday 1-08-2014. A new advisory will be issued tomorrow.
Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856