Tuckerman Ravine has Moderate and Low avalanche danger. Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely but human-triggered avalanches are possible. Evaluate snow and terrain carefully. Lobster Claw, Right Gully, 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. The Lower Snowfields and Little Headwall are not forecasted due to lack of snow though the sluff pile beneath Duchess grew quite a bit this past week.
Huntington Ravine has Moderate and Low avalanche danger. Central Gully has Moderate avalanche hazard. Human-triggered avalanches are possible in this location though natural avalanches are unlikely. All other forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely but continue to watch for unstable snow on isolated terrain features.
AVALANCHE PROBLEM: A widely variable wind slab issue remains the avalanche problem today. Firm (P) wind slabs in Moderate rated areas are a bit softer and smoother than more heavily eroded and textured snow in some Low rated areas. Steeper areas with this firm slab are the primary concern due to the potential to crack the slab over thin spots. Some new and small wind slabs may develop today depending on a potential increase in wind speeds. A complex mix of snowpack condition remain, along with an avalanche hazard that should keep you on your toes as you move around in the terrain.
WEATHER: The weather issue that could affect stability today is the 2-3cm of very light density snow that fell Friday night. Low wind speeds over the past 36 hours have left most of this snow in place where it fell with limiting drifting yesterday morning, when winds gusted into the high 30 mph range. NWS and MWObs forecasts aren’t in alignment regarding wind speeds today so monitor ridgelines for signs of wind transported snow. Temperatures overnight and yesterday have remained near 0F to the low single digits which has not allowed for improved stability. Winds have shifted to the NW already this morning and will continue to shift to the W, potentially increasing to 25-40 mph from where they sit now in the 10mph range. Summit temperature should reach 10 degrees today with a mix of sun, high cloud cover and some summit fog.
SNOWPACK: Crown lines from avalanche activity remain visible in the Lip, across the Center Bowl and near the top of the upper left fork of Hillman’s with debris running from Left Gully across the floor. Signs of avalanches from Central through South gully also highlight Wednesday’s avalanche cycle following the 8” of snow on south winds shifting to the west. Northern gullies received a good scouring while Central, Pinnacle, Odell and South receiving a mix of scouring due to wind and avalanche activity. Expect mostly firm (P) slabs but with a 4 finger to fist hardness weak layer in isolated areas so maintain your safe travel discipline. Older, gray looking snow from the Feb 3-4 melt freeze crust exists in areas too and will provide a more sure-fire stable surface to travel on, though self-arresting on this icy surface would be challenging at best. Firm and smooth snow in Right Gully seemed to yield the best riding conditions yesterday. The Sherburne Ski Trail improved greatly with Wednesday’s storm.
- 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 8:05a.m., March 6, 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