Avalanche Advisory for Tuckerman and Huntington Ravines
Posted: 8:49 a.m., Saturday, December 27, 2003

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

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

The summit received a total of 35.5 cm (14 in) of snow in the past two days. Accompanying winds began from the south and were light. As the storm progressed they increased in intensity and slowly made the shift counterclockwise to the NNW where they've been constant in the 95-110 kph (60-70 mph) range. This has provided plenty of direct loading and cross-loading on many aspects. The density of the falling snow also varied during the storm. We started with high density snow as the storm evolved from the earlier rain, then lightened in density only to revert to the heavy stuff again near the end. This has made for some interesting layers, almost like a whoopie pie if you will. These variables have had significant bearing on the current slab instabilities. In many of the areas rated Moderate today the upper reaches were blasted by the wind and the lower halves are chock full of wind-transported snow. As the definition of Moderate states, these large pockets are unlikely to release naturally but could possibly go if skiers or climbers start hammering on them. As temperatures warm up you should also be on the lookout for rapidly warming pockets that will most likely be located on the heavily loaded south and southeast aspects. This solar gain could trigger some pockets that are sheltered from the wind.

If you are out digging in the snow this weekend it may be interesting to look for faceting due to the extreme temperature gradients. These squareish crystals may be found around the old surface which is now buried. If they develop into a problem we will mention it in upcoming advisories.

In addition to avalanche concerns climbers should expect running water and ice dams. Ice dams can vary in size and impact. They can range from a slight annoyance by getting your gloves wet to a significant problem flushing you down slope with a couple hundred gallons of water. Be cautious and use appropriate protection.

The John Sherburne ski trail has variable conditions due to the recent changes in temperature and precipitation. Expect new snow over areas of ice, some blowouts, abrupt water bars, open holes, and running water.

THE LION HEAD WINTER ROUTE IS OPEN. This is a steep and challenging route. Ice axe, crampons, and the skill to use them well is necessary for safe travel. Remember, it is always easier to go up than come down.

AS ALWAYS, THIS ADVISORY IS ONE MORE TOOL TO HELP YOU MAKE YOUR OWN DECISIONS IN AVALANCHE TERRAIN. It should be used along with your own snow stability assessments, knowledge of safe travel techniques, skill in reading mountain weather's effect on the snowpack, and avalanche rescue.

Please Remember:
•   ****Any new precipitation may increase the avalanche danger, this includes wind transported snow. ****Obtain the latest weather forecast before starting out. ****For more information, contact any of the following: U.S. Forest Service Snow Rangers, AMC at the Pinkham Notch Visitor Center, AMC at the Hermit Lake Shelters, HMC at the Harvard Cabin. ****This avalanche 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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