Posted 8:15 a.m., Tuesday, March 08, 2011
Tuckerman and Huntington Ravines have Low avalanche danger today. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.
Finally, the massive storm that brought inches of unwelcome rain with periods of freezing rain, sleet and snow, has passed. It was a long three days of watching weather models that were giving me a glimmer of hope that the mountains would be buried by feet of snow. That didn’t work out too well. The mountain did pick up between 7 and 12” (18 and 30 cm) of frozen precipitation but freezing rain and rain followed by cold temperatures has left us with a very noticeable crust. As temperatures plummeted yesterday afternoon, some light snow accumulation was recorded on the mountain (around 1” or 2.5 cm). This snow was accompanied by very strong NW winds and has resulted in some isolated areas of new wind slab, primarily in the Lip area of Tuckerman Ravine. This is about the only thing I have to discuss about current snow stability issues! The rest of the snowpack is encased in ice and the free water in the snowpack from all of the rain is freezing. I liken this to watching a newly poured foundation set up. The temperature gradient in the snowpack is impressive and I expect to see faceted snow develop over the next few days. This won’t impact stability any time soon but it is something we will keep an eye on.
If you plan on doing some ice climbing you should approach routes with caution. I suspect ice dams have formed as a result of all the water channels freezing up since the colder air moved in. I would also be suspicious of the overall condition of ice. It just endured at least 2” of rain it may need time to heal the wounds. If you plan on skiing or snowboarding, I’m sorry. You will be battling very icy conditions and/or a thick breakable crust in most areas, including the Sherburne Ski Trail.
On the bright side, it is a beautiful day up here and mountaineers should be able to find something fun to do to enjoy the weather. The Lion Head Trail is well packed so I don’t think you will need to scar your shins breaking the crust on that route. The nice weather will stick around through tomorrow before more precipitation arrives on Thursday. At this time I am not expecting a significant weather maker and the precipitation type is in question. We will keep you posted on this in tomorrow’s advisory.
- 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.
- This advisory expires at midnight. A new advisory will be issued tomorrow.
Brian Johnston, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856