Tuckerman and Huntington Ravines will have CONSIDERABLE avalanche danger today. Natural avalanches will be possible and human-triggered avalanches will be likely. Careful snowpack and weather evaluation, cautious route-finding and conservative decision-making are essential.
AVALANCHE PROBLEM: Light density snow (2-3cm) laying in the alpine zone, which fell Friday, coupled with new snow falling on the summit this morning on increasing winds, will create unstable wind slabs today. Snow plumes indicating wind transport into our avalanche start zones are visible this morning. Wind transport of snow will increase as the wind speed increases, building slabs which will grow in size through the day. Don’t underestimate the size or potential destructive power of wind slabs built from a small amount of snow in our terrain.
WEATHER: Our weather history over the past three days is as important as today’s forecast when calculating snow stability. Since the 2-3cm of snow fell Friday, winds gusted only into the high 30’s mph. Winds have begun to increase this morning into the low 50’s mph and will continue to ramp up through the day, reaching into the 65-85 mph (105-135kph) range from the NW later, with gusts to 100mph (160kph). The wind will also shift to the NW from the current WSW, making snowdrifts all through the alpine zone available to be picked up by the wind and dumped into our forecast area. A trace to two inches of new snow today may add to the potential problem. At this time, snow and light mist are falling at Hermit Lake.
SNOWPACK: We are starting today with a Moderate rating in Sluice, Lip, Center Bowl, and Chute in Tuckerman, as well as Central Gully in Huntington. All other forecast areas in Huntington and Tuckerman are currently rated Low. Temperatures have remained cold since our most recent wind loading event last Wednesday which resulted in widespread avalanche activity. These cold temperatures have not created much bonding and settlement of the pencil hard slabs in our terrain. The hard slabs in place prior to today’s wind loading should have your attention fixed on safe travel techniques if you are planning to use the brief weather window this morning. Hard slabs are stubborn to human triggering but certainly can crack and release an avalanche if you stress a thin spot in the slab.
The Sherburne ski trail has been in good shape lately but ice lurking just beneath recent packed snow will likely show again after the warming trend that’s due to arrive this week.
- 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 8:15a.m., March 7, 2016. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856