Avalanche Advisory for Sunday, January 24, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEMWind slabs continue to be the primary avalanche problem.  Continued cold temperatures have not contributed to a trend towards stability so be aware that the hard windslabs in the Ravine could still fracture. These slabs are thick and strong in most areas of slopes like Right Gully, the Sluice, Left Gully and even lower in Center Bowl where a person would be hard pressed to find a thin spot to create a fracture. In the steepest terrain, it may be possible to trigger a hard slab given a human trigger over a thin and unsupported area or convexity.

WEATHER: Yesterday, overcast skies, calm to light winds with high temperatures in the low to mid-teens F prevailed in the Ravines. Temperatures dipped a bit in the overnight hours with clear skies and light wind leading to colder temperatures settling into the valley. A slight warming trend will bring temperatures into the 20’s F today with 15-30 mph NE then NW winds on the summit increasing later in the day. These wind speeds combined with a lack of available snow for transport will not adversely affect stability.

SNOWPACK: Weather conditions over the past 36 hours have not lead to settlement or sintering and likely have led to some faceting near our now basal ice crust a meter or more down as well as in the softer (1F) wind slab beneath our surface slab. Our low rating comes primarily from the unlikely probability of the weight of a human reaching down to one of these weak layers through the strong, hard (P) surface slab. Primarily planar (Q2) but moderate to hard shears were found in compression tests Saturday between wind slabs and above the ice crust. Currently, some of the most likely spots to find slabs that taper in thickness or are variable in size are also in the most consequential avalanche zones. The Lip and Center Bowl spring to mind where discontinuous but extremely steep (40+degrees) slope angles with complex underlying terrain may create a circumstance for triggering a hard slab. Places like Right Gully and the lower part of Sluice contain some of the thickest and smoothest slabs. Smooth, firm surface conditions may yield to a ski edge but limited boot penetration will challenge those climbing in soft boots or without crampons. Vigorous step kicking in hard boots yields small steps for the forefoot. The hazardous pile of boulders sticking out of the snow in the fall line just below the mouth of Right Gully and upper Lunch Rocks is worth noting making either of these areas an unforgiving spot to miss a turn.

Huntington Ravine, while under a General Bulletin, may harbor some wind slab issues such as at the base of Central, Pinnacle and scattered through Odell and South gullies.  Good visuals show that the northern gullies have limited snow coverage so expect to find long stretches of low angle ice.  The Lion Head Winter Route is now open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are good supplemental tools, but are not substitutes for crampons and an ice axe on this route.  The John Sherburne Ski Trail is passable but becomes harder each day as water ice expands and snow is raked off. Expect challenging conditions.

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. January 24, 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

2016-01-24