Tuckerman Ravine has Moderate and Low avalanche danger. Center Headwall and the Lip have Moderate avalanche danger. Natural avalanches are unlikely but human triggered avalanches are possible. The rest of the forecast areas in Tuckerman Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.
Huntington Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.
Unlike the calm start to yesterday, northwest winds in the 75-85 mph (120-135kph) range on the summit and a temperature 00F(-180C) at 3800ft are making the winter camping routine a bit more challenging for climbers staying overnight at the Harvard Cabin and Hermit Lake. On the positive side, blowing slow and high winds will drop by 10-20 mph (16-32 kph) gradually through the day as temperature readings rise to 00 F (-180C) at the summit and 100 F(-120C) at 4,000 ft. Snow stability will be similar to yesterday due to continued cold and in spite of some additional new as well as wind transported snow. Small pockets of slab, potentially reactive to human triggers, were laid down again last night in some areas of Tuckerman Ravine; enough snow to almost cover the upper 8-10” (20-25 cm) of crown line which were showing beneath the ice yesterday afternoon. Yesterday afternoon and into the night, the wind speed was just right for transporting what remains of available snow for transport out of Bigelow Lawn into those areas. Center Headwall and the Lip are rated Moderate not only because they have a greater potential to avalanche but also due to climbers difficulty in skirting the potential trigger points; recreationists might consider the many other routes available instead. Although still rated at low, an example of other areas to carefully assess include the top right of Hillmans, the top of Left and above the narrows of Chute.
The wind speed and direction last night were also effective at continuing to scour the northern gullies in Huntington Ravine. The top of Damnation has turf at the exit and Yale is showing more ice where easy snow ramps existed before. The ice bulge in Central, which is often alpine ice of the softer variety, is now fresh water ice. These conditions should be factored into a climber’s time and terrain management plan before committing to a route.
Currently, full sun and clear skies are providing good visibility with some minor low level clouds which should clear through the day. Good visibility today will allow for navigation and the micro-level route finding necessary to avoid those isolated areas of wind loaded snow and bullet hard old surface on which self-arrest would be essentially impossible. A few notable areas in Tuckerman to give a wide berth are the Lip and the expanse of snow below it, as well as the bowl-like feature beneath Sluice ice and above Lunch Rocks where the summer Tuckerman Ravine trail traverses left into the Lip.
As mentioned over the past couple of days the old hard surfaces are still causing a traction problem in a number of locales. These old surfaces are camouflaged by newer snow in places and threaten skiers and climbers with long sliding falls.
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 8:45a.m. 1-27-2013. 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