Avalanche Advisory for Tuckerman and Huntington Ravines
Posted: 8:19 a.m., Thursday, February 8, 2007

Tuckerman Ravine has Considerable and Moderate avalanche danger. The Lip, Headwall, and Bowl have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are probable. Unstable slabs are probable in steeper terrain. Be increasingly cautious in steeper terrain. All other forecast areas in Tuckerman Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steep terrain. The Lower Snowfields and Little Headwall are not posted due to a lack of snow in these areas.

Huntington Ravine has Low avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised.

As the Snow Rangers discuss the ratings for the day in our morning meeting it feels a bit like deja vu. For the past three days we have been in the fog with a light flurry of very small spatial dendrites. Upslope snow continued to be the main discussion point as yet another weak moisture starved disturbance slipped by bringing us 1" (2.5cm) of 8% snow over the past 24 hours. Most weather sources believe another inch is likely today while some feel today's deep disturbances may bring us as much as 3" (7.5cm) by midafternoon. We are always on our toes anytime there is upslope snow in the forecast and the temperatures are particularly cold. This allows for lighter density snow and often higher accumulations than we would see otherwise. These events are difficult to forecast for with a high degree of accuracy due to their "pop-up" and spotty nature. The majority of the information from the NWS is pointing to 1" (2.5cm) of new snow today with which we'll concur. However pay attention to what actually happens and adjust your plans accordingly for a safe day. If we move beyond an inch and on to 2-3 inches expect a change in stability given today's 60+mph West winds. Expect "Low" areas to move up a rating and all other locations to be on the upper end of their rating definitions desperately wanting a promotion.

Most of Brian's snowpack discussion in yesterday's advisory is still right on the mark for today and will help the overall feeling of deja vu so I have left his thoughts in quotes. "Cold temperatures are slowing down the sintering process keeping the elastic energy in recently deposited slabs. These slabs vary quite a bit in density depending on where you are. Expect some of them to be hard to kick a boot into while others in very sheltered areas will be softer. The relatively softer slabs will be more prone to human triggers than the ones that make you want your crampons on your feet." The Lip immediately followed by the Bowl and Headwall are the areas of most concern due to new slab deposited in these locales. The northern side of the Bowl and Headwall where they connect with the Lip should contain the highest degree of instability compared with the southern end of the Bowl. This concern is the rationale for the Headwall and Bowl bumping up from yesterday's "Moderate". The past three days have provided us with winds over 100 mph (161 kph) which have scoured snow from numerous areas and deposited it in locations that usually don't have avalanche problems. Stay alert to this during the approach to climbs in Huntington Ravine and down low in the trees.

THE LION HEAD WINTER ROUTE IS OPEN. This is a steep and challenging route. Crampons, an ice axe, and the ability to properly use this equipment are necessary 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, the HMC Caretaker at the Harvard Cabin, and the AMC at Pinkham Notch Visitor Center or Hermit Lake Shelters. This advisory will expire at midnight.

Christopher Joosen, 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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