Avalanche Advisory for Tuckerman and Huntington Ravines
Posted: 8:20 a.m., Saturday, December 29, 2007

Tuckerman Ravine has HIGH avalanche danger today. Natural and human triggered avalanches are likely. Travel in avalanche terrain is not recommended. The Little Headwall has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain.

Huntington Ravine has HIGH avalanche danger today. Natural and human triggered avalanches are likely. Travel in avalanche terrain is not recommended.

A fast-moving storm has deposited 3-4"(8-10cm) of high density snow in the Ravines this morning and looks to stick around for a few more hours. Currently S winds are driving small ice pellets through the air and dumping them off in downwind locations. These ice pellets, along with the needles and large irregular crystals that are mixed in, are forming a relatively heavy, cohesive layer that creates today's main concern. N-facing slopes are benefitting most right now with the current 60mph(97kph) winds but wind direction is expected to shift from the S to the W later today and increase the potential for avalanches in all areas. This change is forecasted to happen around noon with a temporary decrease in wind speeds before they ramp back up and push 80mph(129kph) from the W. Don't get fooled by this short "sucker hole" when conditions temporarily seem inviting and the mountain puts on a mask of benevolence. This is when Mt Washington likes to teach people difficult lessons.

We observed evidence of natural avalanche activity yesterday that occurred under somewhat similar circumstances as we're seeing this morning. Hidden under the fresh blanket of snow are a couple of villanous layers that will stay on our radar for some time. The first is an icy crust that formed following last Sunday's first real rain on snow event of the season. In addition to this textbook bed surface, we'll be tracking the weak layer of graupel and needles, some jumbo-sized, that most likely acted as a weak layer during the last avalanche cycle. Although it helped produce some of the farthest running avalanches of the season, there was not evidence of widespread activity. This points to the potential for today's cycle to step down to this layer and produce some fairly large slides in area's didn't fail yesterday. Remember that the runouts of avalanche paths are just as dangerous as the steep slopes above. This includes the floors of both ravines.

The John Sherburne Ski Trail is open with continuous snow from top to bottom. Expect good snow over a stiff base. THE LION HEAD WINTER ROUTE IS OPEN. This is a steep and challenging route for mountaineers. Crampons, an ice axe and the ability to properly use this equipment are recommended for safe travel on this route.

Please Remember:
•   It is impossible to accurately predict natural events, such as avalanches, in every instance. This Advisory is one tool to help you make your own decisions in avalanche terrain. It should be used along with safe travel techniques, snow stability assessments, an understanding of weather's effect on the snowpack, and proficiency in avalanche rescue.
 
•   You should obtain the latest weather forecast before heading into the mountains. Anticipate a changing avalanche danger when actual weather differs from the National Weather Service forecast.
 
•   For more information, contact the U.S. Forest Service Snow Rangers or the AMC at Pinkham Notch Visitor Center or Hermit Lake Shelters or the HMC caretaker at the Harvard Cabin. This advisory will expire at midnight.

Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856
 
This is the Official Tuckerman Ravine website.  Occasionally the remoteness of Tuckerman Ravine, weather, or communication problems prevent the website from being updated immediately.  Check the date, and if it is not the most recent, you can also call the National Forest Service's 24 hour avalanche hotline at (603) 466-2713 (ext. 4)

Avalanche Advisory Archives.

United States Avalanche Danger Descriptions.

Échelle Canadienne de risque d’avalanche.

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