Avalanche Advisory for Wednesday, January 24, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully has Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Heightened avalanche conditions exist on specific terrain features. Evaluate snow and terrain carefully. Lobster Claw, Right and Left Gully, Hillman’s Highway and Lower Snowfields have Low avalanche danger.  The Little Headwall is mostly open water or waterfall ice and not rated.

AVALANCHE PROBLEM: Areas of wind slab exist in Moderate rated forecast zones. Though small, these slabs are likely to be unstable enough to be triggered by a person traveling on them. Due to the small amount of snow which fell overnight, the size and distribution of these slabs is limited. Low rated areas contain isolated areas of wind slab and will likely receive more scouring and less deposition of new snow. Continued snow shower activity early today may contribute more snow to areas of instability. All of our terrain contains an abundance of stout, icy rain crust which creates a dangerous slide-for-life hazard. Unfortunately, avoiding the wind slabs puts you onto this hard crust. The most imminent threat that will remain constant for the next few days is the icy crust and the potential for a long sliding fall into rocks, stout bushes and holes melted into the snowpack. The Lip contains an unusually nasty fall potential due to the 20’ crown face in the middle of the run and in the fall line of the Tuckerman Ravine Trail.


WEATHER: 2 cm of new snow was recorded at Hermit Lake in the past 24 hours with about 2″ on the summit. Cold air is rushing into the area and replacing the warm moist air with a strong NW wind in the 60-80 mph range. The temperature on the summit has already fallen to 9F and will continue to fall through the day, reaching down to around 0F by dark. Sustained winds in the 70’s mph will also continue through the day and night with gusts to 95 mph. Summit fog will linger today but should clear overnight as the drier air mass takes hold. Anticipate temperatures down to -10F tonight and remain there tomorrow.


SNOWPACK: Another disappointing shot of snow fell in the terrain and failed to cover the icy surface that dominates the terrain following two June-uary thaws. The Alpine Garden and Bigelow Lawn which make up the typical fetch for our terrain have lost a lot of snow. Boulders fields and bushes have a way of holding onto the small snowfall events which can sometimes produce thick wind slabs in our terrain. Anticipate continued icy travel conditions with some drifted snow thrown in to make for engaging hiking and approaches to climbs. Microspikes, crampons and ice axes are all useful now given the firm and icy snowpack.

Please Remember:
• Safe travel in avalanche terrain requires training and experience. This bulletin 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 Harvard Cabin.
• Posted 8:15 a.m., Wednesday, January 24, 2018. 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