Avalanche Advisory for Tuckerman and Huntington Ravines
Posted: 8:51 a.m., Friday, December 21, 2007

Tuckerman Ravine has CONSIDERABLE, MODERATE and LOW avalanche danger today. The Bowl, Headwall and Lip have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are probable. Unstable slabs are probable. Be increasingly cautious in steeper terrain. Hillman's Highway, Left Gully, and Right Gully have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain. All other forecast areas in Tuckerman Ravine have Low avalanche danger. Natural avalanches are very unlikely and human triggered avalanches are unlikely except in isolated pockets. Normal caution is advised.

Huntington Ravine has MODERATE avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible. Use caution in steeper terrain.

The mountain provided an early Christmas present yesterday by picking up a bit more snow than expected. After all was said and done the Summit recorded a total of 6.8" (17.3cm) of new snow by sunset. Densities averaged around 10% although the earliest snow was of a subtantially lighter density than what fell on top of it. The piece of data that is most interesting is the accompanying winds speeds. Yesterday's peak wind gust measured in at 35mph (56kph) out of the SE and the average windspeed was considerably lower. A uniform blanket of fluff covers everything with the only interuptions the tracks of some scattered loose snow sloughs. These conditions occasionally occur on the mountain but rarely do they last for any duration. With this in mind its hard to fathom that today's winds are expected to be similar with only a change in direction to the W and SW and then a small bump up in velocities for Saturday. Right now you're probably thinking about snagging some of the highly elusive Mt Washington powder turns. The good news is that it's possible but of course there's some bad news to go along with it. Areas rated Considerable today developed a layer of windslab stretching from the Chute through the Sluice before being covered by yesterday's snows. The big question is what forces would be necessary to cause failure and fracture in this layer? It might be a large slough or just one person making perfect turns in sweet powder. Many of the area's rated at Moderate today are on the upper end of their forecasted ratings based on the stratification of layer densities. Heavy snow on light snow is always a watch-out situation regardless of whether or not wind is involved. In Tucks the upper portions of Left Gully and Hillman's are of note. In Huntington South and Odell's Gully currently concern us the most but today's WSW winds, although light, have the potential to build some soft slabs in the start zones with easterly aspects such as the top of Central and Pinnacle. An untrained eye will not distinugish the soft slab from unconsolidated snow but you can start to pick them out by watching and feeling how the snow breaks away from boot tracks or swipes with a glove. These amazingly soft slabs can be extremely sensitive so use safe travel techniques and minimize your risk and exposure. Any blowing snow should immediately wave a red flag in your face and blast a fog horn in your ear. As soon as winds pick up to speeds high enough to transport snow you can bet we're going to see some avalanche activity.

High pressure will continue to build into Saturday before Sunday’s weather system moves in. This one looks to be a mix of freezing rain, rain and snow on top. Check the Weekend Update this evening at tuckerman.org to get the latest info.

The John Sherburne Ski Trail is open with continuous snow from top to bottom, however this trail has also been hammered by the wind. THE LION HEAD WINTER ROUTE IS NOW 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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