Avalanche Advisory for Monday, 2-6-2012

Expires 12:00 midnight, 2-6-2012

Tuckerman Ravine has both LOW and MODERATE avalanche danger. The Lobster Claw, Right Gully, Left Gully, and Hillman’s Highway have Low avalanche danger.  Natural and human triggered avalanches are unlikely except in isolated terrain features. All other forecast areas in Tuckerman have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. 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 LOW avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features. Expect these pockets to exist and avoid them by staying to more stable older surfaces. 

I don’t know if it was the game or the long term weather forecast that put Mount Washington in a foul mood this morning, but it’s in a thick, disorienting fog that, every so often, allows a glimpse of underlying irritation and anger. Today the winds will be blowing around the 80-90mph range with stronger gusts later today. Visibility will be poor as well, due to fog and additional snow being transported into the ravines from the other side of the mountain. These conditions will make above-treeline travel challenging. Although some wind loading is expected today, I think there will be insufficient quantities to bump the forecasted danger level above where it was yesterday, so today’s ratings are identical with the exception of Right Gully, which as been dropped to Low danger. This is the result of two factors, one, the distribution of the snowfields in Right being broken up enough that each potential bed surface is isolated and easy enough to mitigate or avoid, and two, the amount of skier and hiker traffic in there yesterday was significant enough to break up any potential surface slabs.

In many areas of Tuckerman and Huntington Ravines, you’ll find very good stability. Left Gully and Hillman’s Highway are examples in Tuckerman where you would have a hard time finding instabilities larger than an isolated pocket. The center of Tuckerman is a different story altogether. In my field assessments yesterday, I found myself thinking, “man, if I were 15 years younger and didn’t know anything about avalanches, these could be the best turns of my life!” Over in the Chute and left side of the Headwall, I was finding a very soft layer of surface snow with a medium-hard slab underneath it. The problem layer was below this slab, as the crust from last Wednesday had been forming a thin layer of early faceted snow on top of it. In numerous stability tests, this is the layer on which the slab failed. The depth and thickness of the layer varied, but in general it existed from the Chute through the Center Bowl. Over in the Right Gully/Sluice area, the faceting wasn’t found. We suspect strong solar radiation on those aspects helped prevent the formation of this layer, but we were still able to get consistent and remarkably easy failures in several snowpit tests. Based on these observations and plentiful visual clues, I’d put the bull’s eye for stability problems right under the ice in the Center Bowl. Working outward from there you will have improving stability, but won’t reach what we’d call Low danger until you get into the Left or Right Gully. Some people did get out and put tracks down in the Sluice and Lip area. Don’t take this as an indication of stability or of the skill and savvy of these people. Whenever you see three people clustered together on a 40 degree windloaded slope with an exposed boulder field for a slide path, it is easy to draw conclusions about the party’s skill level assessing avalanche hazards. Sometimes it’s reasonable to travel on a Moderate-rated slope, but we always recommend only exposing one person at a time to the avalanche hazard.

If you haven’t done so lately, I’d encourage you to browse around on our website and our Facebook page. We’ve slowly been adding features, such as a form for you to submit your own avalanche observations. We’ll be using Facebook as our primary means for giving conditions updates on the Sherburne Trail as well.

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 8:15a.m.  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

2012-02-06 Print Friendly