Posted 8:30am, Saturday, April 23, 2011
Tuckerman Ravine will have CONSIDERABLE, MODERATE and LOW avalanche danger. Hillman’s Highway, Left Gully, the Chute, and Center Bowl will have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. The Sluice and Lip will have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Lobster Claw and Right Gully have Low avalanche danger. Natural and human triggered avalanches are unlikely in these areas.
Huntington Ravine is under a “General Advisory”. You will need to do your own snow stability assessments when using avalanche terrain in Huntington Ravine. A danger of falling ice exists and will persist until it all comes down.
In Friday’s advisory, Chris wrote about the unpredictable fickleness of springtime in New England. Just to prove him right, Mother Nature decided to swing us right back into full winter conditions after yesterday’s warm sunny weather. Avalanche danger will be rising today. We are expecting snow throughout the better part of the day. This will be blown in on strong SW winds, which will quickly work to cover up evidence of yesterday’s Earth Day celebrations (a.k.a. ski, snowboard, and climber tracks). Forecasts today call for winds shifting south to southwest and increasing from 45-60mph to 65-80mph (72-97kph increasing to 97 to 129kph). Snow accumulations might be 2-3″ (5-8cm) before a changeover to mixed types and rain. Most of the new loading will take place in areas such as Hillman’s Highway, Left Gully, and the left side of the Bowl, including the Chute.
To be clear about the avalanche danger, we are starting the day at a solid Low rating. As snow blows in, smooths the bed surface, and then blows in some more, the danger will be on the rise. Later in the day or perhaps in the evening, snow will transition to mixed precipitation types and rain. The rain-on-snow scenario leads us to believe that natural avalanche activity will be possible, hence the Considerable rating. Prior to the rain, two areas have my attention: the top left of Hillman’s and most of the top of Left Gully. These areas are starting the day with exposed rain crust from Wednesday that has not seen much human traffic. In other words, they already have a smooth slick bed surface. They’ll also be in the direct lee of the windblown snow for the duration of the snowfall, allowing them to develop new slab more quickly.
If you think you’re going to get out ahead of the increasing avalanche danger by getting an early start, understand that you’ll be dealing with an icy, abrasive crust that developed overnight and surface conditions that are anything but smooth. The existing surfaces will make a long tumbling fall highly likely if to take a fall in steep terrain. When you think about where you want to go, think about your skills as a mountaineer rather than as a skier or snowboarder, and choose decent routes that are within your climbing abilities. Also, bring your ice axe and crampons! Other hazards exist, such as the waterfall hole and the perils of exiting from the Bowl. I’ll refer you to last night’s Weekend Update for details, or if you’re here just ask a Snow Ranger, ski patroller, or caretaker.
- 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 MWVSP, or the AMC at the Pinkham Notch Visitor Center or Hermit Lake Shelters.
- This advisory expires at midnight. 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