Posted 7:33a.m., Wednesday, January 26, 2011
Tuckerman Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. The only exceptions to this rating are the Little Headwall and Lower Snwofields which both have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these areas.
Huntington Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. The only exceptions to this rating are the Escape Hatch, North and Damnation guillies have Low avalanche danger. Natural and human-triggered avalanches are unlikely in these areas.
Yesterday’s rise to double digits above 0F felt downright balmy on the mountain even though we had snow showers for most of the day. Not only was it good for the body and soul but it should have also been good for the snowpack. Unfortunately the stabilization of the lingering weaknesses in the upper layers of our snowpack has been slow to occur in the days since the mercury plummeted on Saturday. That morning we had a relatively large naturally-triggered avalanche in the Center Bowl of Tuckerman. The weakness on which this slab failed can still be found in both ravines with little change from that morning. Another 1.4”(3.5cm) of light density snow blew in yesterday on W winds with ideal speeds for loading. This created new windslab that has served as an insulating blanket to the cold snow below it. As a result new snow has created new instabilities and helped to preserve those that already existed. The primary areas of concern for new windslab are those with an E aspect. Pinnacle, Central and Yale gullies have climbed up from yesterday’s Low rating and I would be concerned about new soft windslab in the starting zones of all three. In Tuckerman Ravine most areas were rated Moderate yesterday but new snow pushes these areas farther up the continuum within that rating. Dying winds make our concern for naturally-triggered slides take a far second to the potential for avalanches triggered by humans today.
A chance for late day snow showers should be something to watch but we don’t feel like it will play a significant role in today’s stability. A greater chance for snow will move in tonight but what had once been hyped as a “storm” is now looking like it will only provide a few inches of snowfall. At least it will add the potential for more freshies on the Sherburne Ski Trail!
- 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.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856