Tuckerman Ravine has MODERATE and LOW avalanche danger. Sluice, Lip, Center Bowl and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Heightened avalanche conditions exist. Evaluate snow and terrain carefully and identify features of concern. Right and Left Gully and Hillman’s Highway have Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features. Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.
Huntington Ravine has MODERATE and LOW avalanche danger. Central, Pinnacle, Odell, and South gullies have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully and identify features of concern in these areas. All other forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features and well-sheltered lee areas.
AVALANCHE PROBLEM: Wind slab remains the primary avalanche problem. A mix of thicker, more stubborn slabs along with some softer wind slabs are scattered through the terrain. In some sheltered locations these slabs may stretch widely across a gully but in many areas these slabs can be avoided with careful travel. The steepest terrain with lower density wind slabs are the most likely place that you could trigger an avalanche. Thicker, firmer slabs are resting on an icy crust that could release an avalanche in some steeper areas lacking anchors.
WEATHER: Temperatures on the summit bottomed out near -38F late last night and will continue to climb to a slightly more reasonable -11F. Northwest winds in the 40 mph range will keep things wintry but won’t likely transport much snow on the ground. Winds may ramp up a bit through the day before slackening after dark. Good gear including warm mountaineering boots, goggles and face masks will all prove useful today. Being stationary while dealing with even a minor injury could create an extremely difficult situation today.
SNOWPACK: Our limited snowpack this season has slowly grown over the past week but rocks, ice cliffs and bushes still dominate the terrain, at least in the mind of those hoping for good skiing. A firm and icy melt freeze crust is exposed in plenty of the terrain due to the very low density (4%) snow which fell last week being easily moved around by subsequent light to moderate winds. Shifting wind directions and moderate velocities since Thursday have distributed an inch of new snow and redistributed more significant amounts that fell in the middle of last week. Cold temperatures have done nothing to contribute to stability and may even have reversed that trend. The firm wind slabs (P) with lighter density layers of snow (4F-1F) are generally stubborn but have gone mostly untested on most slopes due to cold, low visibility conditions keeping most people off the slopes and gullies. Steeper areas like Sluice, Lip, parts of the Center Bowl and Chute with the softer wind slabs (4F-1F) are also on a slippery bed surface of the Feb 3rd and 4th melt freeze crust. Some of the overlying slabs may be thicker so don’t lure by firmer surfaces into steep terrain without considering that deeper weak interface. Time will tell if faceting near this crust will be a player in instability.
The Lion Head Winter Route offers the quickest route to the summit from the east side of Mt. Washington. The Tuckerman Ravine trail passes across and under avalanche prone slopes in Tuckerman Ravine. The John Sherburne Ski Trail is generally hard packed and wind blown snow with sections of water ice.
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., February 14, 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