Avalanche Advisory for Wednesday, February 17, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman and Huntington Ravines have LOW avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for isolated pockets of snow in strong lee areas.

AVALANCHE PROBLEM: Avalanche problem? Slick icy surfaces, long sliding falls, and ice dams are on my mind more than avalanche problems today. My advice to you is to stick to slope angles well below your usual ability level. Today is not the best day to test your mountaineering prowess, as your ability to self-arrest will be limited by the icy crust. Ice dams will be building in Huntington’s gullies as drainage channels constrict with new ice. Be cautious of this problem, especially near lower angle shelves where water can pool.

As far as avalanches go, the rain and subsequent freeze is working on stabilizing the snow surfaces. We don’t believe all the water has completely drained from the snowpack just yet, but the process is well underway. The trace of snow we received on the tail end of the storm won’t be enough to create any significant instabilities, except perhaps in very strong lee areas if it were to build into deeper drifts.

WEATHER: Precipitation began Monday evening as snow, depositing several inches across the mountain by daybreak on Tuesday. Around this time, temperatures rose above freezing and we began to see rain falling rather than snow. Rain picked up in intensity in the afternoon, with the Observatory recording 0.9″ (2.2cm) of rain from 1-7pm. Total liquid equivalents for the storm snow plus rain were 2.34″  at the summit, with about 1″ (2.5cm) of this coming as snow and the rest was rain. At Hermit Lake, we also received a mix of precipitation totaling 1.7″ (4.3cm) of melted water since yesterday morning.  Temperatures began to fall after dark last night, and by this morning all elevations had been below freezing for a several hours. As skies clear out today, we will continue to learn the total effect this storm.

SNOWPACK: There’s not a lot to talk about this morning. The mountain snowpack is recovering from the hit it took yesterday. Water is draining out, surfaces are freezing from the top downward. We observed a crown line in the Chute leaving wet debris down low, as well as brown streaks indicating runoff in various locations. The Little Headwall took a few steps backward as well, with it mostly being open water now. Expect the current situation to hold until the next round of precipitation comes this weekend. We are hoping for cold temperatures and snow out of that one.

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 8:20a.m., February 17, 2016. A new advisory will be issued tomorrow.

Jeff Lane, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2016-02-17