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.

NOT THE CURRENT FORECAST

This is an archived avalanche forecast and expired on 11/14/2018 at midnight.


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

DateHN24HN24W
(SWE)
Density (%)HSTTotalAir TT MaxT MinSkyPrecipComments
02/19/19
05:20
8 CM 4.2 MM 4%7CM206 CM-16.0 C-7.5 C-20.5 CClearNo precipitation
02/18/19
05:22
Trace Trace NC201 CM-14.5 C-9.0 C-16.5 COvercastSnow
02/17/19
05:24
Trace Trace Trace204 CM-16.5 C-9.5 C-16.5 CClearNo precipitation
02/16/19
05:22
13 CM 10.7 MM 12%13CM205 CM-10.0 C-2.0 C-10.0 COvercastNo precipitation
02/15/19
05:22
Trace 0.1 MM30CM195 CM-7.0 C-5.0 C-15.0 COvercastNo precipitation

Avalanche Log and Summit Weather

Daily Observations


Thank you Mount Washington Observatory for providing daily weather data from the summit of Mount Washington.

DateMax TempMin TempTotal (SWE)24H Snow & IceWind AvgWind Fastest MileFastest Mile DirAvalanche Activity
02/18/199 F-14 F .12 in 2 in32.5 MPH89 MPH

310 (NW)

02/17/1914 F-3 F 0.00 in 0 in37 MPH74 MPH

310 (NW)

View
02/16/198 F-5 F .05 in .8 in52.4 MPH84 MPH

310 (NW)

02/15/1925 F7 F .37 in 2.7 in45.3 MPH84 MPH

240 (WSW)

02/14/1919 F-4 F .13 in 1.1 in56.2 MPH90 MPH

280 (W)

02/13/1916 F0 F .87 in 5.1 in46.3 MPH92 MPH

280 (W)

View
02/12/1912 F2 F .54 in 3.3 in37.5 MPH76 MPH

130 (SE)

02/11/196 F-9 F 0 in 0 in59.0 MPH86 MPH

330 (NNW)

02/10/19-4 F-13 F 0 in 0 in65.3 MPH101 MPH

290 (WNW)

02/09/19-7 F-14 F .01 in .2 in87.5 MPH148 MPH

280 (W)

02/08/1937 F-8 F .20 in .2 in71 MPH124 MPH

230 (SW)

02/07/1934 F22 F .04 in .2 in32.2 MPH56 MPH

250 (WSW)

Please Remember:

Safe travel in avalanche terrain requires training and experience. This forecast 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.

Avalanche danger may change when actual weather differs from the higher summits forecast.

For more information contact the US Forest Service Snow Rangers, AMC visitor services staff at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or seasonally at the Harvard Cabin (generally December 1 through March 31). The Mount Washington Ski Patrol is also available on spring weekends.

Posted 11/14/2018 at 7:00 AM.

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