Avalanche Advisory for Wednesday 1-18-2012

This advisory expires tonight at midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Right Gully, Left Gully, and Hillman’s Highway have Low avalanche danger. Natural and human triggered avalanches are unlikely. 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.

All forecast areas of Huntington Ravine have Low avalanche danger. Natural avalanches are unlikely and human triggered avalanches are unlikely.

There are some stability concerns to be thinking about today, but you might have a challenging time getting to them. Winds today will be gusting from the W to speeds over 100mph (160kph) for most of the day. This will make travel into either ravine difficult enough, but to up the ante, temperatures will fall throughout the day reaching around -5F (-21C) at the summit. Much of the avalanche terrain in the Cutler River Drainage is scoured down to stable snow, thanks to sustained overnight winds peaking at 129mph (209kph). The areas posted at Low danger today are those where this has happened. The exception to this is Right Gully. There is a general lack of snow in the gully, except one large patch on the climbers left side just above the mouth of the gully. Here, the Low rating is more due to this being an isolated pocket within the forecast area than due to scouring.

The locations posted at Moderate today have been the most protected from the strong winds. Last night about an inch of frozen precipitation fell on the mountain while light upslope snow is currently falling. The combination of new snow and the strong winds transporting snow from elsewhere on the mountain is creating a loading situation. I expect any new slabs that will develop in the early hours of today to be dense and strong. It’s often difficult for a person’s impact on a hard slab to be enough to initiate a fracture and failure of the slope, but remember that snow stability is a balance of strength versus stress. When a slope is actively loading it is nearly impossible to accurately assess how this balance is playing out. If avalanche activity occurs today, it would not surprise me if it were naturally triggered from new loading this morning. Saying this, I don’t believe this hazard warrants a greater rating than Moderate. When wind loading comes to a close and skies clear out, it also would not be too much of a surprise to find generally good stability in many of the Moderate rated areas.

 The Sherburne Ski Trail has decent coverage at this time. You don’t need to work too hard to avoid exposed rocks, but you may see a couple. A light amount of new snow under a thin breakable crust will keep your edges on the old surface.  January 20th looks to be the turning point this winter—if not for the winter at least there may be some fresh snow for the weekend. Let’s hope for the best with this one.

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 8:250am. A new advisory will be issued tomorrow.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2012-01-18 Print Friendly