Avalanche Advisory for Tuesday, March 11, 2014

This advisory expires tonight at 12:00 midnight.

Tuckerman Ravine will have CONSIDERABLE and MODERATE avalanche danger today. The Sluice, Lip, Center Bowl, and Chute will have Considerable danger. Dangerous avalanche conditions exist; careful snowpack evaluation, cautious route finding, and conservative decision making are essential. Natural avalanches are possible and human triggered avalanches are likely in these locations. All other forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

Huntington Ravine also has CONSIDERABLE and MODERATE avalanche danger. Central Gully has Considerable danger. Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

AVALANCHE PROBLEM: Developing new wind slab is the avalanche problem causing a rise in danger ratings today. Expect steep slopes with east-facing components to build touchy soft slabs today. In the strongest lee areas, the danger will rise to the point where natural avalanche activity may occur. In adjacent areas, the same problem will exist but the danger will rise to a lesser extent.

WEATHER: A dark cloud looms ominously over Mt. Washington this morning, which is sometimes referred to as “Mt. Doom” by local old timers. Today certainly feels like Mt. Doom is an appropriate name. It’s also hard to focus on today when there is a large winter storm approaching for tomorrow, but we’ll save that discussion for later. Today you’ll be in thick clouds with blowing snow and the possibility for additional upslope snow to be falling. The visibility may be terrible, but at least temperatures will be on the mild side, maybe even going above freezing on the lower portions of the mountain. Westerly winds are the key factor for today, 50-70mph speeds will be redistributing yesterday’s snowfall. And if you were wondering, we received just shy of 2″ of new snow in the last 24 hours. About 1/2″ of this came early yesterday as large stellar dendrites and with light winds. The rest came after dark as winds shifted from the WNW toward the WSW during the latest snowfall period.

SNOWPACK: Looking at how the snow fell yesterday and what the winds were doing will give you a good idea of where today’s avalanche problem lies. Imagine a thin layer of light density crystals floating down from the sky while winds were blowing from the WNW at 30mph. This speed is light enough to allow this layer to land on any aspect, waiting to become a future weak layer. As the second round of snow began, winds ramped up eventually reaching gusts near 70mph from the SW. This pattern likely created sensitive soft slabs sitting on top of a thin weak layer. As we see winds increase again today, additional wind loading on top of these layers will cause danger to rise further.

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 Visitor Center, or the caretakers at Hermit Lake Shelters and Harvard Cabin.
  • Posted 8:10a.m. 03-11-2014. 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

2014-03-11 Print friendly