Avalanche Advisory for Tuesday, 3-27-2011

This advisory expires at midnight, March 27, 2012

Tuckerman Ravine has Low avalanche danger. Natural and human triggered avalanches are unlikely. Huntington Ravine is under a General Advisory. You will need to do your own snow stability assessments when using avalanche terrain in Huntington. A danger of falling ice exists, and will persist until it all comes down.

Yesterday we saw an unfamiliar sight on the mountain…snow! The Observatory is reporting 4.9” (12cm) of 10% density snow, mostly falling between 6am and 6pm. Now before you drop everything and head for the hills with skis and boards in tow, you might want to know that this event didn’t do much to change the conditions in the ravine. It’s still dominated by hard, frozen old surfaces. By the time I had left Hermit Lake at 2pm yesterday, there were approximately 2” (5cm) on the ground and it was blowing around extensively. Winds during the snowfall were very strong; the peak gust at the summit was 113mph (182kph) near mid-day. With winds as strong as these, the new snow was unable to adhere to the frozen and icy old surface. What’s left behind is a lot of icy old surface with very few locations where the new snow has held on. Mostly it’s collected in old boot prints and sluff runnels. It wasn’t even able to fill in the holes that have opened up in the snowpack in the Lip and Headwall area.

With the recent cold snap, the snowpack has gone into a deep freeze. Long sliding falls are a significant threat to mountain travelers for a handful of reasons. First, the slick icy surface allows for rapid acceleration downslope. Second, numerous obstacles may lie below you, in the path of your fall. Lots of rocks have melted out, chunks of ice and rock litter the slopes, trees are exposed, moguls are frozen solid…these all make the sliding fall potential much more hazardous. Consider what would happen if you lost an edge while trying to ski or board. In many places the consequences for fast sliding falls are pretty grim. An ice axe, crampons, and real mountaineering boots are very, very helpful for climbing in these conditions, but even these tools can’t protect you 100%. Much of the terrain here is truly “no fall” territory, even for experts. Don’t put yourself into a situation where you can’t turn back or downclimb. It’s your responsibility to climb and ski within your ability level.

Undermined snow and crevasses have emerged in recent weeks. Overall, the worst of the crevasses can be found in the center headwall, Lip, and Sluice areas. Undermined snow can be found in many locations, including Hillman’s and Left Gully. Until the cold spell breaks and temperatures warm, the snow around these hazards will have good strength, which will help make them less problematic, but you’ll still want to know where they are so you can avoid them. We recommend climbing up what you plan to descend so you can learn about these hazards.

Falling ice should remain in the back of your mind as well. Below-freezing temperatures generally pose less risk than very warm days, but the freeze-thaw cycles can work to dislodge rock and ice from steep terrain, sending it down onto anyone or anything in the runout.

The Sherburne Ski Trail is open about 1/3 of the way down. Expect dust on crust to just barely cover the exposed rocks. There are a couple patches of bare ground and a stream crossing to negotiate before you get to the closure rope. There is a lot of newly frozen water ice on the hiking trails. Traction devices on your feet will be very helpful.

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.  
  • 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

2012-03-27 print friendly