Expires at Midnight
Tuckerman and Huntington Ravines will have CONSIDERABLE avalanche danger today. Natural avalanches are possible and human triggered avalanches are likely. Dangerous avalanche conditions will exist. Careful snowpack evaluation, cautious route finding, and conservative decision making will be essential.
AVALANCHE PROBLEM: Wind Slabs and Storm Slabs are the two main problems. Later today new Wind Slabs will develop as winds pick up from the current 25mph to around 60mph. This velocity increase will trigger another round of loading using yesterday’s snow that is sitting in the alpine zone waiting to be transported. In addition, new snowfall this afternoon will mix in with alpine snow, increasing the volume of available snow. This is the main problem moving the forecast to a widespread “Considerable”.
WEATHER: Over the last 24 hours we have received between 5 and 6” (12.5-15cm) of snow from Pinkham all the way to the Summit. During the majority of the heaviest snowfall winds were in the 30-40mph range. This did set off a cycle late on Tuesday of very soft slabs and dry loose sluffs, as evidenced by many sluff tracks that terminate mid slope without making a full run. Today winds will move from the W to the SW and increase to 60mph midday. Additional snow is expected this afternoon, up to 2” by dark, and another 1-3 tonight. Winds will then get ferocious, with long sharp canines looking to bite. Winds will climb overnight to over 100+mph. If that’s not enough for you, Thursday morning winds will increase and start chomping at anything that moves. Forecasters are taking about 110, 115, 120, >>> and maybe more! Expect today’s visibility to degrade as clouds, snowfall and blowing snow consume the air.
SNOWPACK: Currently at 730am, most areas sit at a solid “Moderate” rating, but will increase to the posted “Considerable” this afternoon. Once winds pick up and begin loading new snow that fell last night you will start seeing new slabs develop, primarily in the upper start zones. As speeds increase, winds will also shift from the W to the SW/SSW. This will load E to NE facing slopes predominately, with areas like Odell and South gully in Huntington, and the Center Bowl through Hillman’s in Tuckerman, being right in the bull’s-eye. These aspects will reach the Considerable rating first with others lingering behind. Some of the S facing slopes will struggle to get out of the Moderate rating, but will eventually. This will all be complicated by additional new snowfall through the afternoon.
If you get out early, before new snow and loading begin, the educated traveler may find slopes that can be negotiated using tactics typically employed during a Moderate rating. Safe travel and route finding, as well as frequent stability evaluations, will be important. However, you should be in and out of avalanche terrain over the next several hours to avoid new instabilities and an increasing hazards. Also consider that it’s vacation week so expect a statistically higher than normal amount of triggers running around the mountain. Be conscience of who may be above and below you.
- 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. Posted 825a.m. 2-19-2014. A new advisory will be issued tomorrow.
Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856