Avalanche Advisory for Sunday, 4-15-2012

This advisory expires at Midnight, April 15, 2012.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice, Lip, and Center Bowl have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas in Tuckerman have 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.

Today has the potential to be another great day for skiing, riding, or hiking, but this mountain presents a wide variety of hazards that you’ll want to be aware of. Rapidly warming temperatures today will exacerbate the usual springtime hazards, predominantly icefall and crevasses. Additionally, there are some avalanche concerns that you need to know about if you plan to be in avalanche terrain, which includes the floor of Tuckerman Ravine and the Lunch Rocks area. Yesterday, skier and snowboarder traffic tested and cut up the slabs in Hillman’s, Left Gully, and the Chute areas. Thanks to them, I feel better about dropping the rating in these locations to Low for today, but if you venture into areas of virgin snow you may find a slab with enough energy to create an avalanche. In the areas posted at Moderate, the concern is primarily related to the rapid warming today. Heat on the snowpack can lead to both stability and instability, depending on how it is applied and the timing. In this case, I’m thinking we’ll have enough warming to break down some of the strength that has developed in the upper layers of the snow, but not enough to fully stabilize the deeper layers. As the upper layer strength is eroded away, your impact as a skier or climber can more easily penetrate and reach those buried weak layers. This will be more problematic in the areas that get the most direct sunlight and have not had significant traffic, namely the Sluice, Lip, and Center Bowl.

Icefall has been occurring from the Headwall and Sluice areas. It is important that you recognize this hazard and take steps to avoid being underneath ice when it falls. Icefall hazard will increase this week as temperatures skyrocket. The greatest icefall hazard exists from the Center Headwall and the Sluice ice above Lunch Rocks. Icefall can happen fast and can be enormous, shattering ice in multiple directions. Lunch Rocks is not be considered a safe place to be. Of course, you should always be looking uphill and thinking about what might fall from above…ice, avalanches, dropped snowboards, people without crampons, etc. can quickly turn a great day into a disaster.

The Center Bowl and Lip area have numerous deep crevasses from earlier warm weather that is now hidden by new snow. Currently, you cannot see where these are, so you will not be able to assess the hazard safely without roping up and probing ahead. Because the consequences of falling into one of these crevasses are severe we recommend avoiding this area entirely. There are some smaller crevasses outside of the Lip and Center Bowl area, and underneath the Sluice ice is another area where we historically have seen very dangerous undermined snow and crevasse hazard.

 Hikers should not plan to use the Tuckerman Ravine Trail to climb to or descend from the alpine zone and the summit of Mt. Washington. From Pinkham, Lion Head and Boott Spur are much better options. The John Sherburne Ski Trail is currently open about halfway down. We expect the skiable terrain to be shortened by tomorrow.

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 Mount Washington Volunteer Ski Patrol, and the AMC at Pinkham Notch or Hermit Lake.  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

PDF version 2012-04-15