Posted 8:00a.m., Monday, December 20, 2010
Tuckerman and Huntington Ravines have Low avalanche danger. Avalanches are unlikely but you should watch for unstable snow on isolated terrain features. We are not currently forecasting for the Little Headwall, Lower Snowfields, Lobster Claw, or Escape Hatch due to an overall lack of snow in these areas.
This past weekend provided favorable conditions for visiting mountaineers. A lack of wind made the cold temperatures reasonable and snow stability was good in most areas. As a result we saw lots of climbers and even a handful of skiers who weren’t afraid to take on the scrappy early season conditions. A number of avalanche courses were out this weekend poking around and many of the students noted the development of faceted snow. These facets have developed as the result of high temperature gradients within our relatively thin snowpack. Facets are currently number one on the stability watch list as their square crystal shape lends itself well to the creation of a persistent weak layer. Although all areas are posted at Low avalanche danger today you’ll want to watch for locations where cohesive windslab covers this loose sugary snow. As of this morning these areas of concern can be classified as isolated pockets but you can bet that we’ll be watching how near-surface facets interface with new snow. An inch or so (2.5cm) of snow is expected overnight and winds are forecasted to finally pick back up. They shouldn’t find too much snow available for transport until around midnight when they’re expected to push to 50mph (80kph) out of the N to NE. If the winds crank up earlier than forecasted an alarm should go off in your head as blowing snow is one of several red flags of instability.
If you plan on heading up the Tuckerman Ravine Trail from Pinkham Notch you should be prepared for about a mile and a half of low angle mixed climbing with long sections of water ice blanketing the entire trail. The lower part of the trail is quite challenging without crampons or other traction footwear and there is the potential to take a nasty fall. Over the past couple days we have noticed blood-stained ice and the tracks of sliding bodies where people’s skill and equipment didn’t match the conditions. Leave a little extra time and energy to navigate this section of trail.
- 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, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Justin Preisendorfer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856