This advisory expires at Midnight.
Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger. The Lip, Center Bowl and Chute have High avalanche danger. Natural avalanches are likely and human-triggered avalanches are very likely. All other forecast areas have Considerable avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely.
Huntington Ravine has CONSIDERABLE avalanche danger. Natural avalanches are possible and human-triggered avalanches are likely in all forecast areas of Huntington Ravine. Dangerous avalanche conditions exist.
Travel in avalanche terrain is not recommended today.
AVALANCHE PROBLEM: Natural wind slab avalanches will be likely to occur in both Ravines today. The floor of Tuckerman Ravine or the Fan and avalanche paths in Huntington will be a risky spot to spend any time today. Snow yesterday evening and overnight along with new snow today will be easily transported by the wind into avalanche start zones and will build wind slabs on east facing aspects while cross-loading others. Northern gullies in Huntington have been more scoured to this point but diminishing wind speeds and continued snowfall will build more wind slabs later today. The likelihood of natural wind slab avalanche in Central, Pinnacle and Odell almost deserve a High danger rating.
WEATHER: 4” of new snow fell on the summit since yesterday afternoon on winds increasing from the 80’s to 100 mph. Light snow is continuing this morning with 1-3” more expected through the day on winds diminishing to the 60-80 mph range. The upslope snow showers will pick up in intensity this afternoon with another 2-4” forecast to fall overnight. Expect seasonable temperatures near 10F on the summit, mid-twenties F at Pinkham Notch.
SNOWPACK: Field time and reported observations yesterday confirmed the existence of a widespread, rime covered crust throughout our terrain. In some areas this crust was on top of (50cm) of loose, granular sleet from the 40% density precipitation that fell Tuesday and overnight Wednesday. This thin crust of ice supported the weight of a skier but was breakable underfoot and was covered in rime which likely makes for decent bonding of the new snow. As is typical with the wind slab problem we frequently deal with here, the failure layer will be in the new snow, probably just above the existing crust. It’s hard to say whether avalanches today and tomorrow will break through this crust and entrain even more mass and resulting destructive power. With low visibility, very high winds creating clear and present signs of a growing wind slab problem, I’d rather not be in the terrain long enough to find out.
The Lion Head Winter Route is open and the most direct route to the summit from the east. Please be careful of bridge construction debris near crossover 7 on the Sherburne Trail when skiing or riding. The recent dense “snow” has resulted in good coverage on the Sherburne which will be a good and relatively wind sheltered place to enjoy the new snow falling today.
- 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 8:40a.m., Friday, January 27, 2017. A new advisory will be issued tomorrow.
Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2713