Avalanche Advisory for Monday, April 9, 2012

This advisory expires at 12:00 midnight, April 9 2012

Tuckerman Ravine has Considerable and Moderate avalanche danger today.  The Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Right Gully, Left Gully, and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. 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.

Three weeks ago, I certainly didn’t see this coming. April often has good winter storms, so we shouldn’t be surprised to come to the day where we’re thinking about the potential for natural avalanche activity. Prior to yesterday, there had been several smaller snow events that laid down a blanket of new snow in strong lee areas of Tuckerman, such as the mid-elevations in the Sluice, Lip, and Center Bowl, as well as in pockets of new snow in most other areas. On Sunday, snowfall began across the higher terrain. This continued through the night, all through Monday, and is still ongoing today. Early in the event there was a period of very light density snow, followed by graupel, followed by increasing density and stronger winds. These winds have been from the N, NNW, NW, and WNW throughout much of this time, though recently they’ve shifted further and are now coming from the W. Snowfall in the last 24 hours was 6.2” at the summit and 5.1” at Hermit Lake. Over the past 48 hours the summit has received about 9” total new snow.

If you’ve spent time studying avalanche behavior on Mt. Washington, you’ll already know where I’m going with this info. Today’s forecast calls for strong W winds in the 50-70mph range and additional snow accumulating potentially to another 6” in favored locations such as Tuckerman. These variables all lead me to believe that natural avalanche activity will be possible in several areas today. Areas posted at Moderate will be increasing in avalanche danger as well. If new snow totals are near the upper end of the forecasted range, the avalanche danger in these areas may exceed the current rating. If you’re traveling into steep terrain today, you’d better bring your A-game and knock the rust off your avalanche skills. Low visibility makes traveling safely in avalanche terrain much more difficult to do. So while it’s critical that you bring avalanche safety gear (i.e. at minimum, a beacon, shovel, and probe), really you need to bring good judgment and the ability to choose your route wisely. It’s all-too-common to see people flock to the area with the lowest danger rating. Doing so today without considering the snow stability issues would not be a prudent move.

As if avalanche danger wasn’t enough to make you stay out of the area, you need to know that the Center Bowl and Lip area have numerous deep crevasses. Expect all of these to be covered entirely by new snow, which makes for weak bridges that can collapse under your weight. You will not be able to assess this hazard safely and the consequences of falling into one of these crevasses are severe, so we recommend avoiding this area entirely. Hikers should not use Tuckerman Ravine to access the alpine zone and the summit of Mt. Washington. Also you should not descend down from these areas into the Ravine. The Lion Head Trail is a much safer option, but you should still be prepared for this trail with an ice axe, crampons, and good winter equipment.

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

2012-04-09 Print Friendly