This advisory expires at midnight.
Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully to identify features of concern. The Lobster Claw, Right Gully, the Lower Snowfields and the Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.
Huntington Ravine has MODERATE and LOW avalanche danger. Central, Pinnacle, Odell, and South gully have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated terrain features.
AVALANCHE PROBLEM: Today’s avalanche problem is Storm Slab and Wind Slab. Although I reluctantly use “Storm” in describing the current slabs, it does fit one of our problems even though we have only received several inches of snow over the past 48 hours. The light to moderate winds this week have created mostly soft wind slab on our largest bed surfaces with an E facing component. Wind Slabs will be more prominent in Tuckerman than in Huntington where forecast areas just meet the “Moderate” criteria. Of all locations you will find the most prominent example of wind slabs in Tuckerman’s Center Bowl and over to the Lip.
WEATHER: Light snow flickered on and off through yesterday, clearing our boot soles, measured 2” (5cm) at 3800ft. Lower elevations got a bit more and higher altitudes a bit less. Winds were again fairly light, continuing our trend of a fairly benign week for Mount Washington and the Presidential Range. Wind speeds were mostly in the high 20’s mph from the SW and peaked at 39, causing light loading on E and NE aspects. We expect a little more snow today with continued moderate winds. The flow will shift from the SW to the W and increase to 45mph before decreasing during the overnight.
SNOWPACK: Although pretty sad, the Snow Ranger mood was almost giddy this morning due to the 5-7cm of new snow. At this point we’ll take what we can get. With the slow accumulation of scant snow totals we have had limited avalanche problems, but we are on a slow trend toward instability. You will start finding a number of new soft layers stacked over one another. These thin slabs, layered with a general 4 finger hardness, will be waiting for more load that may occur this afternoon. The most protected lee slopes, between 35-45 degrees, that face towards the E are hosting our highest concerns and would be the first effected by new snow and loading through the day. Shifting winds to the W and increasing to about 45mph should generate a new round of light loading, moving snow that’s been sitting in the alpine zone and snow falling from the sky. This is the biggest factor to watch today. Pay close attention to our most protected lee slopes, such as in the Center Bowl, to be moving to the upper end of the Moderate rating. Although to a lesser extent than the Center Tuckerman Bowl, you may see new slab develop high in start zones such as Huntington’s Odell and Central as well as Tuckerman’s Left Gully and Chute. We will verify this in our field work today and discuss more in the Weekend update later today.
OTHER HAZARDS: There is still a lot of ice out there hidden by a veneer of new snow. The Tuckerman Trail from Pinkham and the Sherburne Ski Trail has an astounding amount of ice. Crampons and an ice ax are essential for travel in steeper terrain.
- 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 830a.m. Friday 1-17-2014. A new advisory will be issued tomorrow.
Christopher Joosen, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856