Avalanche Advisory for Sunday, March 5, 2017

This advisory expires at Midnight.

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Lip has Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely. The Little Headwall is not forecast due to lack of snow.

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

AVALANCHE PROBLEM: Signs of natural avalanche activity occurring last night due to wind loading of the scant amount of snow that has fallen the past couple of days has raised concerns for human-triggered avalanches today. With the exception of the Lip and right side of Center Bowl, most of these wind slabs will be on the smaller side. Look for smooth areas of snow that will contrast easily with nearby old, gray snow or new, wind eroded sastrugi snow. Test these wind slabs for signs of instability before committing to the slope. The larger fetch upwind of Tuckerman made more snow available for larger wind slabs to develop in the Lip with pockets in Sluice and Center Bowl. Central Gully in Huntington also has pockets of wind slab that are bordering on the Moderate danger rating while most of the rest of the gullies are scoured.

WEATHER: Current temperature on the summit is -11F with -1F at Pinkham Notch. Wind is from the NW at 60 mph and will diminish a bit through the day to the 45-60mph range. The temperature will warm and ultimately reach 0F by the end of the day under sunny skies. Seems like a great summit day, with excellent visibility, if you keep your skin covered.

SNOWPACK: Signs of the recent warm up are largely gone and have been replaced by signs of winter. The waterfall hole in the Lip as well as the Little Headwall have refrozen and most of Huntington and much of Tuckerman Ravine are showing refrozen, hard snow surfaces. There is a surprising amount of new snow across the Headwall and Sluice so be sure to keep in mind that our snowpack and avalanche paths remain expansive and more than capable of producing dangerous avalanches when we get new snow. A crown line low in the Lip is a good reminder that wind slabs develop with even small amounts of snow this time of year when the plateau downwind of Tuckerman and to a lesser extent, Huntington, are smoothed out by a substantial snowpack. This means that every bit of new snow that falls can be transported by the wind into avalanche start zones in leeward areas.

OTHER HAZARDS:

  • Glide cracks, moats and crevasses have opened in places and are just concealed with new snow. The hole above the above the Open Book low in the Lip forecast area would be worth avoiding if traveling on foot.

Please Remember:

  • 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  8:00 a.m., Sunday, March 5, 2017. 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

2017-03-05