Avalanche Advisory 1-8-2012

Expires 12:00 midnight, January 8, 2012

Tuckerman Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible. Heightened avalanche conditions exist on specific terrain features; evaluate snow and terrain carefully and identify features of concern. The exception to this rating is Hillman’s Highway which has Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features. Some areas are not yet posted due to the overall lack of snow. These include Lobster Claw, Right Gully, the Lower Snowfields, and the Little Headwall in Tuckerman. Forecasts for these locations will begin when conditions warrant.

Huntington Ravine has Moderate and Low avalanche danger today. Yale, Central, Pinnacle, and Odell have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. North, Damnation, and South gullies have Low avalanche danger. Natural and human triggered avalanches are unlikely. The Escape Hatch is not posted.

Today is starting out as a blustery foggy day in the ravines, but there is hope for some clearing this afternoon as high pressure slowly builds in. What we’re seeing this morning are the remnants of a weak weather system that dropped a small amount of snow across Mt. Washington late yesterday and overnight. A total of 1.1” (2.7cm) of light density snow was recorded on the summit. During this time, winds were from the west, blowing in the 50-70mph (80-113kph) range. New snow loading is contributing to today’s forecasted rating, as are the observations from our field trip yesterday. The snowpack on Saturday had some good strength to it in many areas, though there were also numerous locations that left me believing the snowpack remained in the lower end of the Moderate rating since human triggered avalanches were more “possible” than “unlikely.” Added to the lingering instabilities, we now have an additional layer of wind-transported snow to think about, as well as a slight potential for more snow this morning. While a meager inch of snow isn’t really all that much, the vast majority of the stability problems on this mountain are created by the ability of winds to multiply snowfall into much deeper slabs in lee areas. The potential weak layer and bed surface combination will change depending on where exactly you go.

The areas we’re most concerned with today are those in the lee of westerly winds. In Huntington, areas near the top of the approaches before the ice climbs begin may hold unstable slabs. Also expect to find pockets of snow in the tops of many gullies, including the ones that are rated Low today. In Tuckerman the Lip and Center Bowl would be the areas to be most concerned with. As you move through these locations you’ll find the snow underfoot changes quickly from place to place. We moved Left Gully up to Moderate today due to its ability to build slabs in the upper section under these ideal wind loading conditions. Today I believe an avalanche savvy traveler could work his or her way through many of the Moderate rated areas, but if you blindly head into steep terrain without paying attention to the snowpack you may very well trigger an avalanche.

The Sherburne Ski Trail took a hit yesterday with temperatures rising above freezing. Expect lots of brush and sections with water ice as well as breakable crust.

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 8:30a.m., Sunday January 8, 2012. 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

Printable Advisory (revised)