This advisory expires tonight at 12:00 midnight.
All forecast areas of Tuckerman and Huntington Ravine have LOW avalanche danger. Natural and human triggered avalanches are unlikely except in isolated pockets. The Lobster Claw, Lower Snowfields, and Little Headwall are not posted due to an overall lack of snow in these areas.
AVALANCHE PROBLEM: Pockets of Wind Slab are the avalanche problem today. The rain and melt water in the snowpack from the recent weather maker is now freezing quickly as temperatures continue to plummet over the past 18 hours. This newly frozen surface will act as the bed surface for the light snow which added up to between 2.5″ (6cm) and 3″(7.5cm) on the Washington summit last night. Expect pockets of new wind slab in strong lee areas such as below steep roll overs, steep water ice, rock buttresses, etc.
WEATHER: Since yesterday afternoon, the summit mercury has fallen from +34F to -4F and continues to drop. Upslope snow showers, from yesterday afternoon until now, have added up to about 3″ (7.5cm) but should start tapering off this morning. Expect below 0F temperatures and west winds in the 60-70 mph range with low visibility this morning creating challenging travel conditions above treeline. Winds should shift from the NW later with an increasing wind speed, peaking above 90mph (144kph).
SNOWPACK: Unfortunately, the Ravines are shrouded in frozen fog this morning and obscuring the view of signs of recent avalanche activity. The heavy rain and warm temperatures fell on a mix of old melt freeze crust as well as more recent, predominantly pencil hard, wind slabs. Wet avalanches are notoriously difficult to predict but we are expecting to see signs of it in many areas, hopefully later today if the summits clear. The rain wreaked havoc on the already boney east side trails, as you might expect. Water ice floes stretch wall to wall on the Tuckerman Ravine trail as well as the Sherburne ski trail. Though the stretches of blue water ice slowly decrease in size and extent with altitude, there is still boilerplate, refrozen snow in most places. There is a dusting of the new snow and drifts due to the high winds this morning. I would not even think of leaving Pinkham parking lot without microspikes on much less leaving sharp, steel crampons in the car. The Lion Head Winter Route is likely to be a mix of refrozen crust (neve) along with ice and bare rock making for higher consequences and more challenging climbing than in heavier snow years.
- 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 8:20am, February 26, 2016. A new advisory will be issued tomorrow.
Chris Joosen/Frank Carus, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856