This advisory expires at Midnight Sunday 1-22-2012
Tuckerman Ravine has MODERATE and CONSIDERABLE avalanche danger. The Lip, Center Bowl, and Chute have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route finding and conservative decision making is essential. Right Gully, the Sluice, Left Gully, and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.
Huntington Ravine has MODERATE and CONSIDERABLE avalanche danger. Central gully, Pinnacle, Odell, and South Gully have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route finding and conservative decision making is essential. North, Damnation, Yale, and the Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.
Once again we were teetering on the fence between forecast ratings again today. Based on the atypical low snow density storm event from Thursday and Friday we have decided to hang on to the Considerable rating for a number of locations that were in the direct lee of West winds. These winds were the dominate direction for the majority of the loading over the past 72 hours. Areas that dropped a rating from Considerable you might call “Scary Moderate”. There is a fine line between human triggers being “very possible” (upper end of Moderate) and “likely” (Considerable). Therefore, recognize that although areas posted at Moderate have more snow stability than the higher rated Considerable locations, many do not linger far behind. If you decide to go into Moderate posted locales today do not fall asleep at the wheel and give the snowpack a good assessment. The big factor for all this is the soft slabs that developed over loose unconsolidated low density snow Thursday though Saturday associated with very cold temperatures. Cold air in place over the region has done little to consolidate or stabilize slabs so the upper snowpack has been sitting in homeostasis. They have changed very little over the past 2 or 3 days and are waiting for enough time or a slight weather change to stabilize. The other element that could make a change in the snowpack, I.e. fracture and failure, is YOU. I would be very cautious venturing into soft slabs and choose your routes carefully. You will find instabilities and slabs vulnerable to human triggers without looking to hard particularly on East facing slopes in the strong lee. Don’t let the blue bird day suck you into the uncontrollable desire for powder. Be objective with your analysis and don’t convince yourself everything is fine if you don’t have the data to say that.
I haven’t said anything about natural avalanche activity potential because it is not too much of a concern. Dying winds, lack of loading and a slight warm up towards 20F shouldn’t be enough to cause natural slope failures. But, that will be a different story tomorrow as we move into……. ah yes good ole New England Wintry Mix, aka “mountain slop”, and eventually….rain. What will freezing rain and rain do to cold soft slabs that have been sitting between -5 and zero degree temperatures you ask? AVALANCHE! So the return of natural avalanches issues will likely be the case Monday and Tuesday. The bright side is this could hit the reset button wiping out instabilities and bridging others making them moot. More on all that tomorrow.
We have switched the Lion Head ascent from the Summer Lion Head trail to the Winter route. The summer trail is not recommended due to the snowfield traverses near treeline and their associated avalanche risk. Follow the orange signs marking the route at the bottom off the Tuckerman Ravine trail and at treeline where it rejoins the summer trail above the Summer trail avalanche problems.
The Sherburne Ski Trail has decent coverage. Be cautious for some buried landmines and waterbars as they still are problem particularly when you can’t see them.
- 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. Posted 8:45am. A new advisory will be issued tomorrow.
Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856