Avalanche Advisory for Monday, 4-2-2012

This advisory expires at 12:00 midnight, April 2, 2012

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Lip, Center Bowl, Chute, and Left Gully have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible. Right Gully and Hillman’s Highway have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to lack of snow.

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.

Well, we’re back into avalanche forecasting mode again. The mountain picked up 4” of light density snow (3.6%) yesterday afternoon and evening while winds remained virtually non-existent. This left behind a blanket of fluff that may act as a weak layer for future slabs to build onto. We expect this scenario to play out today, as winds will increase in velocity and shift from the N to the NW, ending the day in the 45-60mph (72-97kph) range. Through the day, the wind will be working to pick up and transport the snow that is currently sitting in the alpine zone. I suspect some of the new snow will be able to hide out in the rocks and vegetation, which will prevent loading from being as robust as it might be if we were in mid-winter conditions up high. But while there might be some limitations to what is available, I’m confident that there is sufficient snow to build new windslab. The key to understanding today’s avalanche danger is that the trend is for increasing avalanche danger through the day. Windloading will move most areas up through Low and into Moderate territory. Only time will tell for certain how far up the scale we go today. It may be into the upper end of the Moderate rating, or if loading is truly limited, it may just barely make it above Low.

In addition to the avalanche potential today, there are other significant hazards you need to be aware of, some of which are a little different this season than most years. Crevasses, undermined snow, and waterfall holes are a serious threat. Currently the area from the Sluice to the Center Bowl is littered with crevasses. Many of these are covered with a thin coating of newer snow, which makes them nearly impossible to safely assess their exact location and depth. We spent a lot of time yesterday looking into these problem areas, and I personally came away from the experience with a strong sense of humility and fragility. The hazards presented by the crevasses are not to be taken lightly; it is truly “no-fall” terrain. Taking into account the extent of crevasses, the severity of the consequences, and the inability to assess the hazard, I highly recommend avoiding the Lip area entirely, which includes the area of Tuckerman Ravine hiking trail.

Surfaces will be icy and hard below the new snow, so long sliding falls are another significant threat. The slick surface will allow for rapid acceleration down slope potentially sending you into numerous obstacles below you. An ice axe, full 10-12 point crampons, and real mountaineering boots are absolutely critical for climbing in these conditions safely. The hard surface beneath the new snow makes belayed climbing on the steeper slopes a wise technique.  Because the current surface conditions have made most steep slopes “no fall” territory, the experience and skills to use technical mountaineering equipment is imperative.

The Harvard Cabin is now closed for the season. The only camping permitted in the Cutler River Drainage is at Hermit Lake Shelters. The Sherburne Ski Trail is open about 1/3 of the way down and is in surprisingly good shape. Cross over to the hiking trail at the rope.

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, the caretaker 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

 2012-04-02 Print Friendly