Avalanche Advisory for Monday, 4-23-2012

This advisory expires at 12:00 midnight, April 23, 2012

Tuckerman Ravine has 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. A danger of falling ice exists, and will persist until it all comes down.

As you sit in your warm dry space today, thinking of the mountains and how they will react to the rain, here are some thoughts to ponder. So far, the mountain has received about 1.6″ of rain since precipitation began Saturday evening. There is potential for another couple inches, or, if we’re in a “localized area of higher amounts,” then maybe even more. First, think about what it would be like if temperatures were 20 or 30 degrees colder. This would be a great nor’easter dumping huge snowfalls across all of New England. But sadly it’s not. So instead think about water percolating down through the snowpack, collecting and channeling into little streamlets. These combine and form bigger streams that run beneath the snow and ice. As rain becomes heavy today, picture the water level in these streams rising, possibly exceeding the capacity of the drainage channels and pushing the overflow upward onto the snowpack. Historically, we’ve had some pretty exceptional wet snow avalanches as a result of heavy spring rains. I think the probability is low for this to happen today, mainly because the drainage channels are already well established and large. But, if this unlikely event did take place, I would want to be nowhere near Tuckerman Ravine when it happened. Since the thought did enter my mind this morning, I figured I’d give you something to think about, whether you’re in your cubicle or actually headed up onto the mountain. A much more likely scenario today is the worsening of the usual springtime hazards of falling ice, crevasses, and undermining. Low visibility will make all of these hazards difficult to assess.

ICEFALL will continue to be a significant issue, especially as rain melts the bonds between rock and ice. Many people have been injured or killed through the years by falling ice. A number of people had some very close calls earlier this week, including one woman being nearly decapitated by a disk of ice the size of a garbage can lid. That piece missed her, but her partner was injured in the thigh by a much smaller chunk. Although we often think of the large potential, it’s worth remembering that even a small piece of ice impacting you at high speed can cause a lot of damage. Ice and rock has been falling from a variety of locations, including the less common areas such as Left Gully, the Chute, and Right Gully. The areas at greatest risk are Lunch Rocks, the Center Bowl, and the floor of the ravine. Presently, if you’ve reached the snow line in the floor, you’re within striking distance of icefall!

CREVASSES exist in many areas and rival icefall as the primary concern for visitors. Always climb up what you plan on descending so you can assess the hazards at a more leisurely pace.  The Lip and Headwall have the largest crevasses but smaller slots have grown in the Sluice, Left Headwall, and the Chute. Undermining or running water has increased the collapse hazards near holes, rock and crevasses as well.  The lower sections of Hillman’s Highway have become discontinuous due the snowpack collapsing near the exposed rocks.

THE TUCKERMAN RAVINE TRAIL IS CLOSED TO ALL USE FROM LUNCH ROCKS TO THE JUNCTION WITH THE ALPINE GARDEN TRAIL. This includes the Lip area as well as this section of the hiking trail. The trail to the floor of the ravine is open, as is the section from the summit down to the Alpine Garden junction. This annual closure is due to the magnitude of crevasses and undermining that develop in this area during the spring melt-out. A fall in this area would have severe consequences.

The John Sherburne Ski trail is now closed to all use.

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, the caretaker at Hermit Lake Shelters.
  • 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

2012-04-23 Print Friendly