This advisory expires at 12:00 midnight.
Tuckerman Ravine has Considerable and Low avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway will have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas have Low avalanche danger. Expect heightened avalanche conditions on specific terrain features.
All forecast areas of Huntington Ravine have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely.
AVALANCHE PROBLEM: Wind Slabs forming this afternoon and evening are the primary avalanche problem. Increasing, shifting winds and new snow will cause avalanche danger to increase through the day. As a result of anticipated wind loading, natural avalanches will be possible in many areas of Tuckerman and Huntington Ravine.
WEATHER: Light southwest winds this morning will increase in speed and shift to the west towards midday effectively transporting recent snowfall into avalanche start zones. The timing window for the increasing wind directly effects our hazard rating for today. Currently, about 2.5″ of snow from the past three days and 3.5″ of older snow grains are available for transport in the Alpine Garden. Local history has shown that this amount is more than enough to yield substantial wind slabs particularly if the 1-3″ of accumulating snow shower activity this morning comes to fruition. Summit fog, snow showers, and later ground blizzards will conspire to reduce visibility and challenge a traveler in the ravines to move safely through avalanche terrain. The slow ramp up of velocity will build unstable slabs over the new snow with instabilities due to the weak interface.
SNOWPACK: Within the 5-6″ mentioned above lies a thin sun crust from Wednesdays blazing sunshine. Beneath all that, the old surface is icy and hard, and occasionally exposed in some steeper and/or windblown areas. Our snowpack in today’s Low rated areas in Tuckerman, as well as the northern gullies in Huntington, are still bare due to the melt cycles brought by protracted January thaws. Sluff piles beneath steep terrain features will also increase in size today.
OTHER HAZARDS: There is still a lot of ice and hard crusts out there hidden by a veneer of new snow. Ski poles and various foot traction will be helpful getting to Hermit Lake or the Harvard Cabin. Crampons and an ice ax are essential for travel in steeper terrain. The Lion Head Winter Route has limited snow cover, so it is a very steep icy mountaineering route at this time. Expect crowded slow moving conditions as people try to negotiate the steep sections safely.
- 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. Sunday 1-19-2014. 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