Avalanche Advisory for Saturday, March 19, 2016

Tuckerman Ravine has Moderate and Low avalanche danger.  Sluice, Lip and Chute have Moderate avalanche danger. Natural avalanches and unlikely but human-triggered avalanches are possible there. All other forecast areas have Low avalanche danger. Natural and human-triggered avalanches are unlikely. Lobster Claw, the Lower Snowfields, and Little Headwall are not posted due to a lack of snow in these areas.

All areas of Huntington Ravines have MODERATE avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.

AVALANCHE PROBLEM: Today’s main avalanche problem is Wind Slab.  Six inches snow over the past two days is driving this avalanche problem and ratings.  West winds have deposited this snow in lee areas creating the possibility for human-triggered avalanches. New, thin crown lines (2-3″ thick) visible yesterday afternoon and this morning in Chute and Center Bowl plus signs of heavy scouring and wind packing have allowed a Low rating in these areas though I would certainly stay heads up if venturing into Low rated terrain today.

WEATHER: Unseasonably cold weather is on tap for today with summit temperatures struggling to reach 0F from the current -6F. Biting north west winds, 50-70mph, appear to be diminishing a bit already and are expected to drop to a slightly more hospitable 35-50mph later today. Still a cold day in store for folks in our terrain.

SNOWPACK: Last week’s melting and rain followed by cold conditions has created a situation that doesn’t have us too concerned about deep instabilities.  The main focus for us is new snow over the past 48 hours.  Although Huntington is socked in with clouds and blowing snow but good visibility in Tuckerman Ravine has allowed visual assessment.  Snow on Wednesday began warm so generally the early bonding was good.  Since then new snow has contained a fair amount of rimed particles or graupel that don’t bond well or turn into smaller fragments with good sintering potential. Expect some pockets to be more touchy than you might think due these particles as well as the cold temperatures which may have recrystallized snow grains near the crust interface.  We don’t believe instabilities are widespread, but expect a high degree of spatial variability.  Like yesterday, you will be on hard old surface one second and into some slabs the next.

 Other typical spring hazards include:

  • Long sliding falls – Crampons are highly recommended in steep terrain. Snowshoes and microspikes are no substitute. Spring weather brings variable snow surface conditions that change by the hour and by aspect. Arresting a fall on an icy 30+ degree slope is practically impossible.
  • Crevasses, moats and waterfall holes – Warm water flowing under the snow pack creates holes and thin spots in surface snow that are deep enough to injure or kill you. New snow can obscure the openings.
  • Falling ice – Cold temperatures are putting this hazard on the back burner for the weekend.

TRAILS INFO:

  • The Tuckerman Ravine Trail uphill from Pinkham to Hermit Lake is mostly wall-to-wall ice. Traction devices or crampons are necessary for reasonable travel on this trail.
  • The Lion Head Summer Trail is open. The winter route is now closed.
  • The Sherburne Trail is closed about 2/3 mile up from the parking lot. Please respect the closure by walking over to the Tucks trail at the rope to reduce erosion on the ski trail.

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 8:15a.m., Saturday, March 19, 2016. A new advisory will be issued tomorrow.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2716

2016-03-19