Posted 8:15a.m., Saturday, March 19, 2011
Tuckerman and Huntington Ravines have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.
Well, this morning’s weather isn’t exactly what I thought I’d be walking into. Arriving at Pinkham and on the ride up to Hermit Lake there was a surprising amount of snow in the air. A little more than an inch (3cm) was measured at the Hermit Lake snow plot, with very light density (<4%). The Harvard Cabin plot measured a little less, and the Mt Washington Observatory isn’t forecasting much more to fall throughout the day. This is good news if you are looking for stable snow, since our only stability concern at this time stems from any windloading of this new snow that happens today. The weather trend for today includes clearing skies and diminishing wind speeds, so I expect new loading to be minimal. While this won’t greatly affect stability in the ravines, there is a chance you’ll find isolated pockets of soft slab here and there. With winds from the NW and WNW, the largest of these will mostly be found in lee areas such as the Sluice, Lip, and Center Bowl in Tuckerman. Any windblown snow will fall onto an icy frozen crust that developed overnight. This may provide for poor adhesion between the new snow and the crust. Although everything is posted at Low, you will want to watch out for deeper accumulations of this morning’s snowfall.
The frozen crust will make conditions challenging for those without the proper equipment and skills. Long sliding falls will be a threat to people who either don’t have an ice axe and crampons or for some reason find themselves unable to self-arrest. When conditions get really hard and icy, even experienced mountaineers can find it difficult to arrest a fall before accelerating beyond the point of no return. When you really need it, a pair of ski poles is not a good substitute for an ice axe. This includes travelers heading up Lion Head as well as into the ravines. The Lion Head Winter Route is a steep route; an ice axe and crampons are recommended for this area. And before I get off my soapbox, it’s always a good idea to take off your crampons if you’re going to do any glissading–your ankles, tibias, fibulas, and knees will thank you for keeping them intact.
- 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.
Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856