Avalanche Advisory for Tuesday, January 16, 2018

Huntington and Tuckerman Ravines have LOW avalanche danger. Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. The Little Headwall is an open stream and is not rated.

AVALANCHE PROBLEM: Today’s limited snow showers falling on a very hard refrozen upper snowpack keep our avalanche concerns to a minimum. The timing of the incoming snowstorm looks as though insufficient snow will fall to merit new stability problems before this advisory expires at midnight. Other hazards should play a greater role in your travel decisions today, which include but are not limited to:

  • Long sliding falls are all but certain if you lose your footing high on a steep slope. Crampons, ice axe, and your ability to use them are essential for travel on snow slopes today. Microspikes are an effective tool on icy trails but are no substitute for crampons on firm snow slopes. Realize that the hardness of surface snow will make arresting a fall with an ice axe very challenging and that recently exposed rocks elevate the consequences of such a fall.
  • Ice dams blowouts are common on our ice climbs in conditions like this when significant water flows under ice. These can cause a myriad of problems and have been the source of fatal accidents.

WEATHER: A trace of snow early this morning is bringing a wintry look to the area but has not altered our firm surface snow conditions. Today will become increasingly cloudy as snow showers develop that could bring up to an inch of new snow. Temperature should remain around 10F on the summit, dropping slightly later today. West wind is forecast to increase towards 50 mph before shifting SW and decreasing tonight. Tomorrow will bring a handful in inches of snow with continued moderate SW wind.

SNOWPACK: A thick layer of hard refrozen snow encapsulates our remaining snowpack. Thickness of this layer varies spatially with the degree to which recent rain saturated the upper snowpack, but seems to be at least a few inches to over a foot. Needless to say, this is a supportable crust in the alpine and requires good crampon and ice axe skills to travel in steep terrain. Snow today should not accumulate enough to warrant new stability issues with potential to harm a person. This could change tomorrow following more snowfall. As discussed above, other mountain hazards are quite relevant today. Though disappointing for snow lovers, the weather of the past week illustrated the mountain’s ability to produce extraordinary avalanche events, as evidenced by Friday’s massive wet snow avalanche. It’s an important reminder of the power of snow on a steep slope.

The John Sherburne Ski Trail has a large area where flowing water melted all snow. Combined with firm conditions and a rough refrozen snow surface in places, it’s not a great ski option. For travel on foot, areas of water flowing across and down the trails had similar though less drastic effects. The Lion Head Winter Route remains open with varied conditions including snow, ice, dirt, and rock.

Please Remember:
• Safe travel in avalanche terrain requires training and experience. This bulletin 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 Harvard Cabin.
• Posted 7:30 a.m., Tuesday, January 16, 2018. A new advisory will be issued tomorrow.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-1-16