Avalanche Advisory for Monday, 4-16-2012

This advisory expires at midnight, April 16, 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.

Wow, I thought Sunday was warm, but it’s already warmer on the summit today than it got to all day yesterday, and it’s not even 7am yet. The intense heat the mountain will see today will create some hazardous conditions, and I’m not just talking about sunburn and dehydration. Avalanches, crevasses, undermined snow, and falling ice should be on your mind as you travel through the ravines. If you are looking to get off the beaten path, you’ll likely find deep wet snow, saturated with water and completely unsupportive. Yesterday in Tuckerman there were a handful of loose wet snow avalanches. A couple were triggered by falling ice in the Sluice, and the debris from one buried the top of Lunch Rocks where several people had been lounging around just one day earlier. Today you can expect similar types of loose wet avalanches. With early cloud cover, heating will be more evenly distributed, so the hazard won’t be driven entirely by the slope’s aspect relative to the sun. As clouds clear in the afternoon, the solar energy will certainly intensify heating on the south-facing slopes, increasing the potential for this to take place. This type of avalanche is different from the more typical slab avalanche, whether dry or wet slabs. While a large one can definitely produce enough debris to bury a person, the greater problem is related to the weight of the wet snow. The stuff is so incredibly heavy that it can easily sweep you off your feet. I would expect to see the majority of these today to be from the Center Bowl, Lip, and Sluice. I also believe there may be a slight chance that the snowpack will remain cohesive enough to propagate a slab avalanche, but I feel the likelihood is low enough for the current ratings to best describe the overall avalanche potential. Remember, just because it’s mid-April does not mean you should ignore the red flags of avalanche danger, such as rapid or prolonged warming.

Falling Ice will happen today; I’m willing to bet on it. It is important that you recognize this hazard and take steps to avoid being underneath ice when it falls. The greatest icefall hazard exists from the Center Headwall and the Sluice ice above Lunch Rocks, though yesterday we saw ice falling in Left Gully, the Chute, and Right Gully as well! Icefall can happen fast and can be enormous, shattering ice in multiple directions. Lunch Rocks is not be considered a safe place to be. Regardless of where you are, 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 AMC at Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters. 
  • 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


2012-04-16 Wet loose debris on Lunch Rocks