General Bulletin for Wednesday, November 21, 2018

This forecast was published 11/21/2018 at 7:00 AM.
A new bulletin will be issued when conditions warrant.

The Mount Washington Avalanche Center will no longer issue daily avalanche forecasts for the 2018/19 season. Read more

The Mount Washington Avalanche Center will no longer issue daily avalanche forecasts for the 2018/19 season. Instead, we will post an updated General Bulletin as needed, in case of significant snow or weather events that might vary from the typical daily changes that come with spring weather. We will also keep you informed about the official closure of the portion of the Tuckerman Ravine Trail from Lunch Rocks through the Lip and Headwall as well as the switch from the Lion Head Winter Route to the summer trail. Observations from the field will continue to be a valuable resource, so please keep submitting photos, videos and observations here and we will do the same. Check the Forecast page for update on Sherburne Trail closures, which are imminent as spring snowmelt continues.

The switch to a General Bulletin does NOT mean that the mountains are now a safe place to ski. The hazards which emerge in the spring are significant and require careful assessment and strategic management. If you have never skied Tuckerman, peruse our Incidents and Accidents page for spring related incidents involving avalanches, long sliding falls, icefall, crevasse and moat falls, and other incidents related to diurnal changes in the snowpack. These will help you understand and plan for these hazards.


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

Terrain around Mount Washington continues to collect snow with snowfields increasing in size. Some avalanche paths are growing rapidly while others still continue to harbor more rocks and brush than snow. While snowfields are growing, most avalanche paths are not quite fully developed. Traditional start zones have not yet filled in, but smaller avalanches are occurring in areas that have enough snow. These same areas are the places getting attention from skiers and climbers. With the early season stoke in high effect at the moment and many people trying to ski and climb, it’s important to remember the basics: travel one at a time and make use of safe zones, avoid skiing or climbing under or above another party, and bring your avalanche rescue gear.

 

Danger Rating by Zone

Over that last four days, the summit of Mount Washington recorded over 15″ of new snow. The 4″ that fell yesterday arrived on lighter winds and will be subject to strong W and NW winds through the remainder of the week and into the weekend. In addition, another 2-4″ is forecast for higher elevations Wednesday afternoon. Strong wind should continue to transport any available snow to the east side of the mountain range, further developing snowfields in lee areas of steep, extreme terrain. Bed surfaces are currently a mixed bag with terrain appearing to change on a daily basis as cliffs and ice bulges turn into snowfields. Over the course of the holiday, the weather forecast looks clear and windy, with the big story being the cold. Be prepared for mid-winter conditions if venturing into avalanche terrain with equipment to make snowpack assessments and to be self-reliant should the need arise. Respect small pockets of potentially unstable snow which have historically been the culprit of early season avalanche accidents on both ice climbs and larger snow slopes. In addition to avalanche hazards, be mindful of 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, heightening the consequences of a fall or 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.  Consider using a rope in third class terrain or sooner than normal due to the slick surface.

The summer Lion Head Trail remains a preferred east side route to the summit over the Tuckerman and Huntington Ravine Trails, though watch for our recommendation towards the Winter Route that will come with additional snowpack development.

Avalanche Safety Information Study

Please contribute to the effort to improve backcountry avalanche forecasts! Researchers in Canada devised a study to better understand how we communicate the avalanche risk, and we need your help. Please fill out this survey. It will take a few minutes, but it will help us as we work on new ways to give you the most important avalanche information.

Snow Plot Information

DateHN24HN24W
(SWE)
Density (%)HSTTotalAir TT MaxT MinSkyPrecipComments
05/31/19
05:20
0 CMTrace 0CM0 CM8.0 C11.0 C0.5 CBrokenNo precipitation
05/30/19
05:25
0 CM 0.0 MM0CM0 CM7.5 C7.5 C1.0 CScatteredNo precipitation
05/29/19
05:25
0 CM 22.3 MM0CM0 CM1.5 C4.0 C0.0 COvercastNo precipitation
05/28/19
05:25
0 CM 0.0 MM0CM0 CM0.5 C11.0 C0.5 CClearNo precipitation
05/27/19
05:15
0 CM 0.0 MM0CM10 CM8.0 C15.5 C8.0 CClearNo precipitation

Avalanche Log and Summit Weather

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
05/30/1946 F36 F 0 in 0 in27.9 MPH55 MPH

290 (WNW)

05/29/1947 F33 F 0 in 0 in20 MPH48 MPH

290 (WNW)

05/28/1934 F28 F .71 in 3.7 in20 MPH48 MPH

290 (WNW)

05/27/1940 F27 FTrace 0 in38.9 MPH68 MPH

300 (WNW)

05/26/1948 F39 F .77 in 0 in48.7 MPH75 MPH

290 (WNW)

05/25/1947 F31 F .42 in 0 in17.7 MPH63 MPH

240 (WSW)

05/24/1942 F32 F .66 in 0 in44.8 MPH105 MPH

05/23/1944 F30 F .16 in 0 in26.8 MPH71 MPH

270 (W)

05/22/1934 F21 F 0 in 0 in36.2 MPH115 MPH

330 (NNW)

05/21/1934 F23 F .57 in 1.9 in73 MPH135 MPH

330 (NNW)

05/20/1951 F33 F 0.57 in 0.0 in48 MPH82 MPH

250 (WSW)

05/19/1951 F34 F .6 in 0 in34.2 MPH66 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 11/21/2018 at 7:00 AM.

Helon Hoffer Snow Ranger
USDA Forest Service
White Mountain National Forest