Avalanche Advisory for Sunday 1-20-2013

This advisory expires at 12:00 midnight, January 20, 2013

All forecast areas of Tuckerman Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.  The only exceptions to this rating are the Lower Snowfields and Little Headwall, which have Low avalanche danger. In these two locations, natural and human triggered avalanches are unlikely.

All forecast areas of Huntington Ravine have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The only exception to this rating is Escape Hatch, which has Low avalanche danger.

Change is the word of the day today, as in, the conditions on the mountain will quickly change during the day today. This applies both to weather and avalanche conditions. The AMC caretaker described the weather this morning as “deceptively benign,” and I definitely agree with his assessment. Winds are already increasing in speed and are expected to gust to around 100mph (162kph) by early afternoon. Temperatures will also be dropping, clouds will descend over the mountain, and snow showers will add some excitement to the day. In fact, in the time I’ve taken to write this advisory, this change has already begun.

As for avalanches, we’re starting the day with a Moderate rating in most areas. As the weather today deteriorates, new snowfall will mix with older snow that is being picked up from windward locations and redistributed into the lee slopes of Tuckerman and Huntington. This will create an increasing avalanche hazard, though we expect the overall hazard to remain in the Moderate range for most of the forecast period. Toward the end of the day, some areas will be at the upper end of the Moderate range, possibly pushing into Considerable if snowfall totals are at or exceed forecasted amounts.

In Huntington, the areas of greatest concern are the tops of Central, Pinnacle, and Odell. Approaching these climbs can put you into recently deposited windslabs before you even swing your tools into the ice. These locations would be the first to reach the upper end of Moderate today. North and Damnation lie on the other end of the spectrum. They are starting the day with a mostly wind scoured surface down low and only thin snow coverage at the top. New snow loading today will bring these areas up into the Moderate rating, but they are starting the day with low avalanche hazard. The overall lack of snow in the Escape Hatch leads to its Low rating. I wouldn’t recommend this route until we get more snow.

Tuckerman currently has a mixed bag of snow surfaces. There is exposed melt-freeze crust peppered around the ravine leftover from last weekend’s warmth. The largest areas of exposed crust can be found in the lower Sluice, above the Open Book, and above the Lip. In the Center Bowl and Chute, you’ll find deeper drifts formed as recently as last night. It’s a good bet that these softer drifts of new snow will have a greater likelihood of avalanching when subjected to an additional load. Skiers and snowboarders take notice, this is the snow you will want to ski or ride more than anywhere else in the ravine but it is also the most dangerous. Again, avalanche hazard will be rising today with new snow and blowing snow loading on strong W winds. On the whole, you should be trying to avoid protected lee areas where the loading will be most pronounced.

The Little Headwall is not in good shape for skiing or riding; it was a raging waterfall just last Monday. Reports from the Sherburne yesterday are overwhelmingly positive.

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 8:45am, January 20, 2013. 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

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