Avalanche Advisory for Saturday, 1-21-2012

Expires at Midnight Saturday 1-21-2012

Tuckerman and Huntington Ravines 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. 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.

Most importantly this morning realize we have just come down from HIGH danger last night and I believe we are at the upper end of the CONSIDERABLE danger rating for all forecast areas.  Maximum winds gusting into the upper sixties and low seventies occurred around dark last night.  This was possibly the period of highest instabilities as denser slabs were being developed in the Ravines from the west winds.  Loading this morning has slowed down substantially which makes the High rating definition of naturals being “likely” a bit over stated.  This makes the Considerable rating  of naturals “possible” more accurate.  However, an additional 1-2” (2.5-5cm) of snow today, with West winds from 30-40+ mph, will keep a threat of natural activity a potential, so be mindful of new loading rates.  The concern that stands out in my mind today is the human triggered avalanche menace.  With cold air hovering around the 0F (-18C) mark today, yesterday’s slabs have not consolidated much at all.  A building wind on Friday created soft slabs over a loose unconsolidated 3.5% snow acting as the weak layer for these new problems to fail on.  Joe and I found unstable snow near treeline yesterday during the late morning and early afternoon.  In locations that didn’t avalanche overnight I would expect a human triggered avalanche to be “likely” in new slabs.  We anticipate continued touchy instabilities across the Ravines until the clouds and new snow subside enough to see what has already avalanched and what didn’t.  A big caution with these instabilities is it’s a Saturday, so plenty of human triggers will be running around perhaps using your ascent as a decent.  Compounding this is the low visibility from clouds and blowing snow.  Some typical descents are Right Gully in Tuckerman and South and the Escape Hatch in Huntington.  Although I can’t recommend being in these locations, based on the instabilities, at all realize that additional risk may be present from above.  Obviously fresh tracks ahead of you should also scream “run away”.  It is a head’s up day!

We have switched the Lion Head ascent from the Summer Lion Head trail to the Winter route yesterday morning.  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 at this time with a fresh 6-7” of fluff. Be cautious for some buried landmines and waterbars as they still are problem particularly when you can’t see them.    

 Please Remember:

  • 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 8:15am. 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

 2012-01-21 Print Friendly