Posted 7:11am, Monday, April 25, 2011
All forecast areas of Tuckerman Ravine have Low avalanche danger. Natural and human triggered avalanches are unlikely.
Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington Ravine. A danger of falling ice exists and will persist until it all comes down.
It’ll be another warm cloudy day in the ravines. If we have any luck, the 30 percent chance of rain will not materialize and we’ll just see clouds hanging over our heads all day. The chance for rain increases dramatically after dark. Summit temperatures are expected to rise up into the upper 30’sF (2-4C), which will allow all snow surfaces to remain soft. The risk of avalanches under today’s conditions remains Low, but you can still expect to see some wet sluffing since ravine temperatures have been above freezing for some time now. The cloud layer is just above the ravine at this time, and it looks very thick. Plan for poor visibility today, but we can at least hope for the summits to be in the clear.
As the melt out begins in earnest, the annual springtime hazards are beginning to show themselves. Yesterday I took a look at some of the crevasses that are opening up in the Headwall, and they are still on the small side. While they won’t swallow you whole, you might punch through on your climb up or catch a ski on your way down. Give these more room than you may think is needed. Icefall is going to become an issue in the coming days as well. Currently the largest of the ice pieces appear to be holding on, but it’s only a matter of time before it all comes down. Probably the most notable hazard you’ll face today will be UNDERMINED SNOW. This is when the snow bridges are eroded away from below and weakened by warm weather. Collapsing through, whether into a stream bed, crevasses, or the dreaded waterfall hole itself, can have dire consequences. You’ll want to evaluate the thickness and strength of snow bridges carefully before trusting them to hold your weight.
The bottoms of the hiking trail and the John Sherburne Ski Trail are melting out quickly. Currently the ski trail is still open all the way to Pinkham Notch. Moguls are abrupt and abundant, and the thin sections are transitioning to longer stretches of bare ground. We’ll be monitoring the rate of decay and start closing off the bottom sections of trail when it becomes necessary.
- 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 MWVSP, or the AMC at the Pinkham Notch Visitor Center or Hermit Lake Shelters.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856