General Bulletin for Wednesdat, November 14, 2018

This forecast was published 11/14/2018 at 7:00 AM.
A new bulletin will be issued when conditions warrant.


The Bottom Line

General Bulletins are issued when unstable snow may exist within our forecast areas but before 5 scale avalanche advisories begin. Please remember that avalanches can occur before 5-scale avalanche forecasts are issued. This bulletin expires at midnight, Friday, November 16, 2018.

After a fitful but early start, winter is taking a solid hold on higher elevation terrain. Snow is beginning to fill in the windswept alpine zone and the mercury is dipping well below the zero mark. Snowfields are growing in size while boulder strewn gullies, cliffs and trees are beginning to be covered by wind-blown snow. All this adds up to conditions which can produce enough snow to build wind slab avalanches along with the bed surfaces needed for the avalanches to slide on. Signs of natural avalanche activity were observed in October before a warming trend melted much of the 52” of snow that fell in the latter half of that month. The recent downward trend in daily temperatures and passing storms is allowing the snow to accumulate once again. Avalanche debris was recently observed in the shady and sheltered aspects on the south side of Tuckerman Ravine. Tuesday the 13th brought another shot of snow followed by plummeting temperatures and extreme winds in excess of 100 mph. Winds of this velocity have a history of scouring many areas while building rock hard wind slabs in more sheltered spots. The next storm, which is forecast to arrive Thursday night, will bring more potential for unstable storm and wind slabs on growing snowfields.

Forecast Area

Photo taken Saturday, Nov, 11 showing runouts of Left Gully and the Chute in Tuckerman Ravine. More snow and windloading occurred Nov. 13 and 14.

These snowfields could produce consequential avalanches in many areas of steep terrain. Ice climbs are growing in size and pockets of unstable snow between ice pitches are notorious for causing problems.  In addition to avalanche hazards, remember to take into account other early season hazards that exist in the terrain:

  • Rocks, trees and bushes lurk in the snow and in the fall line. Skiing or sliding into obstacles can ruin your day or worse. New snow may just barely cover a season ending stump or boulder.
  • Terrain traps and cliffs make burial and significant injury a real possibility, even if you are only swept off your feet by a small avalanche.
  • Long sliding falls are a threat despite the appearance of new, soft snow on your approach. Wind can easily scour parts of your climb or hike down to a hard bed surface. What you thought would be a mellow snow climb can turn into something much more exciting. Don’t count on self-arrest to save you. Protect yourself with a rope and/or don’t fall.
  • Recent, rapidly falling temperatures stress the outer surface of the ice and create brittle conditions. These same conditions can lead to ice dam formation where flowing water is trapped behind freshly formed ice. Be mindful of tool swings when you hear water and approach top outs.

The summer Lion Head Trail remains the safer east side route to the summit than the Tuckerman and Huntington Ravine Trails. Weather forecasts indicate that the Lion Head Winter Route may soon become a better alternative as snow fields grow and allow avalanches to threaten the summer trail. Be sure to ask about the switch or be prepared to travel in avalanche terrain on the summer trail.

Snow Plot Information

Date24HHN24W
(SWE)
DensityTotalAir TT MaxT MinSkyPrecip
12/16/18
05:24
0 CM 0 MM106 CM-8.5 C-1.0 C-10.0 CClearNo precipitation
12/15/18
05:25
0 CM 0 MM108 CM-1.0 C-1.0 C-17.5 COvercastNo precipitation
12/14/18
05:38
0 CM 0 MM108 CM-4.0 C-3.0 C-17.5 CClearNo precipitation
12/13/18
05:25
1 CM 0.1 MM110 CM-17.0 C-11.0 C-19.0 CClearNo precipitation
12/12/18
05:35
2 CM 0.1 MM110 CM-11.0 C-7.5 C-15.0 CObscuredSnow

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, the Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.

Posted 11/14/2018 at 7:00 AM. A new bulletin will be issued when conditions warrant.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest