This advisory expires at 12:00 midnight, Thursday, April 30, 2014.
Tuckerman and Huntington Ravines are under a late season General Avalanche Advisory. You will need to do your own snow stability assessments when traveling in avalanche terrain. General Advisories are valid for no more than three days, but may be updated earlier as conditions warrant.
This is a late season General Advisory, which is different from advisories using the 5-scale danger rating system. It’s important for you to understand that there may be unstable snow while a GA is in effect. Instabilities may come in many forms, such as wind slab, wet slab, loose wet snow, etc. We most often use GAs late in the season after the snowpack has stabilized to the point where day-to-day weather changes are not going to drastically affect snow stability. But remember, you are ultimately responsible for making your own assessments of snow stability when using avalanche terrain.
This upcoming week we expect to see rain and generally unsettled weather over the mountain. Even in a springtime snowpack, rain can exacerbate a lot of problems. In addition to the annual spring hazards listed below, a heavy rain event can cause large destructive wet slab avalanches, particularly in the Lip. At this time of year, I would not personally recommend traveling into Tuckerman during a heavy rain event, due to the variety and magnitude of hazards present.
FALLING ICE is a very dangerous situation. The largest ice looms in the Sluice above Lunch Rocks, in the Center Bowl of Tuckerman, and throughout much of Huntington. Other areas pose this threat as well, though to a lesser extent. The best advice we can give is to not spend time underneath areas where ice may fall. Large rocks may provide some cover, but they have proven themselves in the past to be inadequate shields for people hiding behind them. Lunch Rocks is a hazardous location when icefall is a possibility!
CREVASSES AND WATERFALL HOLES are another potentially lethal hazard. Each season these form in many areas, the worst are in the Sluice, Lip, and Center Bowl. Many of these holes follow stream courses under the snowpack with icy water spraying around. We anticipate these hazards to be increasing in magnitude throughout this week.
UNDERMINED SNOW is related to the hazard above. It occurs when streams have eroded away the snowpack from below, but left behind a bridge of snow. This bridge can collapse without warning under your weight, bringing you into the icy stream below. Give wide berth to areas that have already collapsed or show signs of sagging or cracking.
LONG SLIDING FALLS are probably the #1 cause of injury each spring. Cold temperatures cause the soft corn snow to refreeze into a slick and solid mass of ice. We always recommend an ice axe and crampons for travel in steep terrain. You may not need them always, but if the unexpected happens these tools, and the ability to use them effectively, can save you from serious injury or death.
The Lion Head Winter Route is still open. The bottom half of the John Sherburne Ski Trail is closed. Please cross over to the hiking trail at the closure rope and hike the rest of the way down to Pinkham.
- 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.
- Posted 7:15 a.m. April 29, 2014. A new advisory will be issued Friday, May 2.
Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856