General Bulletin for Tuckerman Ravine

This is the final bulletin issued by the Mount Washington Avalanche Center for the 2017-18 season. It will remain in effect until complete melt out. Travel in the backcountry requires careful snow evaluation and mountain sense. Hazards due to snow and ice will persist until both are all gone. Summer snowstorms on Mount Washington are uncommon, but not unheard of. If venturing into the mountains, be sure to use all available resources to help plan your trip and make safe travel decisions.

MOUNTAIN HAZARDS

  • Falling Ice and Rocks: While the largest pieces of ice have already fallen this spring, smaller areas of ice linger and will continue to present a threat until fully melted out. Rocks can also become dislodged and fall as melting ice and snow recedes. Overhead assessment and safe travel techniques will help to manage this hazard.
  • Crevasses (glide cracks): Gravity slowly pulls our deep snowpack downhill as it melts, causing large cracks to open. These cracks present a significant fall hazard. Widespread in the Lip, they develop in much of our terrain and can be surprisingly large and deep.
  • Holes and Undermined Snow: Flowing meltwater can melt the snowpack from beneath. As this hollowing takes place, unpredictable collapses will occur. Some are more obvious like the famous snow arch near Lunch Rocks but others are less so, like a sudden hole appearing in the floor of the Ravine.

TRAIL CONDITIONS

  • The summer Lion Head Trail is open and provides the most direct route to the summit of Mount Washington from Pinkham Notch.
  • A section of the Tuckerman Ravine Trail is closed. This section extends from Lunch Rocks in the ravine to the junction with the Alpine Garden Trail above the ravine. The closure is due to severe and possibly fatal consequences of a fall into deep crevasses and holes in the snow. Skiing or riding this area, which includes the Lip, is also not allowed. This section of trail will remain closed until the snow melts from the trail. Check with the visitor’s center or the caretaker at Hermit Lake for the current status.
  • The John Sherburne Ski Trail is closed for the season. You will need to hike all the way from the Bowl or Hillman’s Highway back to Pinkham. The Sherburne Ski Trail is especially muddy this year and needs time to grow the grass and plants that will control erosion.

ATTENTION AUX RANDONNEURS! Une section du sentier du Tuckerman Ravine est présentement fermé à toutes les activités.  Cette section est située entre Lunch Rocks et le sommet du Headwall jusqu’où ce dernier rejoint le sentier du Alpine Garden. Cette fermeture inclut également toute activité de descente dans le secteur du Lip. Seulement cette section du sentier est fermé. Cette fermeture annuelle est due à l’ampleur des crevasses et à la gravité qu’occasionnerait une chute dans ce secteur.

Thank you to all of our partners and volunteers, including the Mount Washington Volunteer Ski Patrol, the AMC and the caretakers at Hermit Lake and the Harvard Cabin, the Friends of Tuckerman Ravine, White Mountain Avalanche Education Foundation, and many others. Thanks to all of you who have volunteered your time or your money to help with projects and rescues. Our mission is to serve the public and we count on support from the community to make that happen. Also, we look forward to seeing you on November 3rd at the Eastern Snow and Avalanche Workshop held again this year at the Performing Arts Center in Fryeburg, Maine. Stay tuned to our social media channels and this website for news, upcoming talks in your region and of course, for avalanche bulletins next fall.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This bulletin is just one tool to help you make your own decisions. You control your own risk by choosing where, when, and how you travel.
  • For more information contact the Androscoggin Ranger District, the AMC Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters.
  • Posted at 7:00 am on Tuesday, May 22, 2018.

Frank Carus, Ryan Matz, Helon Hoffer; Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-20_General

General Bulletin for Tuckerman Ravine

We are no longer issuing daily avalanche advisories for Tuckerman Ravine this season. However, we will continue to provide snowpack and weather information when conditions change. Avalanches, falling ice and rock, snow undermined by water, large glide cracks, and icy refrozen surfaces all remain potential threats until melt out is complete. We are no longer monitoring conditions in Huntington Ravine, but similar hazards will also persist until snow and ice is gone.

The beginning of this week comes with warming weather. Summit temperatures should remain above freezing for the next few days. A weather disturbance could bring clouds, rain, and thunderstorms on Tuesday, with a potential return to sunnier skies by Wednesday. Cooler temperatures are possible later in the week, keeping all of the classic spring hazards listed below relevant this week.

Due to open glide cracks and undermined snow, the Tuckerman Ravine Trail is now closed in the Ravine between Lunch Rocks and its junction with the Alpine Garden Trail. This closure includes the Lip area, which presents numerous hazards to the recreating public and potential rescuers alike.

The following hazards have all caused fatalities and should influence your terrain choices:

  •  Long sliding falls: The melt/freeze cycles of spring can make good corn snow when the snow is not frozen. When frozen, the icy snow is makes travel more difficult and can virtually eliminate your ability to arrest a fall. This refreeze can occur remarkably fast, potentially turning a good ski descent into a conditions better served by crampon and ice axe travel.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity, the slow creep downhill leaves cracks, sometimes called crevasses, in much of our terrain. This is especially prevalent in the Lip, where a large waterfall hole is also present and growing. These cracks and holes will continue to grow. The waterfall area of the Lip has spawned large and destructive wet slab avalanches in the past during periods of heavy rain.
  • Icefall: All ice in the ravines will fall down at some point due to warm weather, often in large chunks that travel at high rates of speed. The center and looker’s right portions of Tuckerman Ravine are most exposed to icefall due to the ice in Sluice and Center Bowl. Lunch rocks is a particularly inappropriate place to linger. Consider than speed is safety when passing under any ice flow.
  • Undermined snow: In addition to melting on the surface, the snowpack is eroded by meltwater flowing beneath. This creates thin snow bridges that will collapse and are most common over streams and in upper portions of south facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.

The Tuckerman Ravine Trail is now closed between Lunch Rocks in the ravine and the junction with the Alpine Garden Trail above the ravine. The significant fall hazard of large glide cracks and waterfall holes result in this annual closure. The Lion Head Summer Trail is now open. Be prepared for a range of conditions including a steep snow slope above a significant fall hazard. Crampons and an ice axe are recommended in firm snow conditions. The Sherburne Ski Trail is now closed due to lack of snow. Plan to hike up and down from Tuckerman Ravine. Skinning is not the option preferred by most any longer.

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  8:40 AM, Monday, May 14, 2018. A new bulletin will be issued when conditions warrant.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-14-General

General Bulletin for Tuckerman Ravine

We are no longer issuing daily avalanche advisories for Tuckerman Ravine this season. We will continue to provide snowpack and weather information as conditions change. We are no longer monitoring conditions in Huntington Ravine, but similar hazards will persist there until snow and ice is gone.

Temperatures at night will dip below freezing with daytimes temps into the 30’s on Saturday and near 40 on Sunday. Generally sunny skies with some clouds will allow snow to soften for skiing but also loosen up ice and weaken snow bridges. Watch the temperatures and clouds carefully to be sure your corn skiing won’t turn into a potential slide-for-life situation. As always, don’t linger under ice cliffs. A warming trend this week will continue to melt our remaining snow which is holding up pretty well in the Bowl for this time of year. As temperatures warm, remember to manage your sluffs. The Lip is nearing closure with open waterfall holes, which have been the scene of a number of fatalities, in the fall line.

All of the following hazards have caused fatalities and should influence your terrain choices:

  • Long sliding falls: The melt/freeze cycles of spring can make good corn snow when the snow is not frozen. When frozen, the icy snow is makes travel more difficult and can virtually eliminate your ability to arrest a fall. This refreeze can occur remarkably fast, potentially turning a good ski descent into conditions better served by crampon and ice axe travel.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity, the slow creep downhill leaves cracks, sometimes called crevasses, in much of our terrain. This is especially prevalent in the Lip, where a large waterfall hole is also present and growing. These cracks and holes will continue to grow. The waterfall area of the Lip has spawned large and destructive wet slab avalanches in the past during periods of heavy rain.
  • Icefall: All ice in the ravines will fall down at some point due to warm weather, often in large chunks that travel at high rates of speed. The center and looker’s right portions of Tuckerman Ravine are most exposed to icefall due to the ice in Sluice and Center Bowl. Lunch rocks is a particularly inappropriate place to linger. Consider than speed is safety when passing under any ice flow.
  • Undermined snow: In addition to melting on the surface, the snowpack is eroded by meltwater flowing beneath. This creates thin snow bridges that will collapse and are most common over streams and in upper portions of south facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.

 The Sherburne Ski Trail is now closed due to lack of snow. Plan to hike up and down from Tuckerman Ravine. Skinning is not the option preferred by most any longer. The Lion Head Summer Trail is now open. Be prepared for a range of conditions including a steep snow slope above a significant fall hazard. Crampons and an ice axe are recommended in firm snow conditions.

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  8:40 AM, Saturday, May 12, 2018. A new bulletin will be issued when conditions warrant.

Frank Carus, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-12 General Bulletin

General Bulletin for Tuckerman Ravine

We are no longer issuing daily avalanche advisories for Tuckerman Ravine this season. However, we will continue to provide snowpack and weather information when conditions change. Avalanches, falling ice and rock, snow undermined by water, large glide cracks, and icy refrozen surfaces all remain potential threats until melt out is complete. We are no longer monitoring conditions in Huntington Ravine, but similar hazards will also persist until snow and ice is gone.

Cool weather will give way to an approaching warm front, though temperatures should remain somewhat cold through the weekend. The summit is forecast to remain below freezing today. Intermittent and partial cloud cover is forecast to continue through tomorrow. Saturday will also bring a chance of rain showers as temperatures warm by a few degrees. Wind today will gust to 90 mph but diminish by afternoon. Warming temperatures on Sunday may allow loose wet sluffing to again become a concern, but until then, the potential for icy refrozen snow makes long sliding falls a primary hazard. Cloud cover and a chance of showers makes Saturday not ideal for skiing. Sunday looks like a sunny day with soft snow. Glide cracks continue to grow and will soon result in closure of the Lip area.

The following hazards have all caused fatalities and should influence your terrain choices:

  • Long sliding falls: The melt/freeze cycles of spring can make good corn snow when the snow is not frozen. When frozen, the icy snow is makes travel more difficult and can virtually eliminate your ability to arrest a fall. This refreeze can occur remarkably fast, potentially turning a good ski descent into a conditions better served by crampon and ice axe travel.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity, the slow creep downhill leaves cracks, sometimes called crevasses, in much of our terrain. This is especially prevalent in the Lip, where a large waterfall hole is also present and growing. These cracks and holes will continue to grow. The waterfall area of the Lip has spawned large and destructive wet slab avalanches in the past during periods of heavy rain.
  • Icefall: All ice in the ravines will fall down at some point due to warm weather, often in large chunks that travel at high rates of speed. The center and looker’s right portions of Tuckerman Ravine are most exposed to icefall due to the ice in Sluice and Center Bowl. Lunch rocks is a particularly inappropriate place to linger. Consider than speed is safety when passing under any ice flow.
  • Undermined snow: In addition to melting on the surface, the snowpack is eroded by meltwater flowing beneath. This creates thin snow bridges that will collapse and are most common over streams and in upper portions of south facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.

 The Sherburne Ski Trail is now closed due to lack of snow. Plan to hike both up and down from Tuckerman Ravine. The Winter Lion Head Route is still open due to the amount of snow remaining on the summer trail.

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  8:40 AM, Friday, May 11, 2018. A new bulletin will be issued when conditions warrant.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-11-General

General Bulletin for Tuckerman Ravine

We are no longer issuing daily avalanche advisories this season for Tuckerman Ravine, however, we will continue to provide snowpack and weather information when conditions change. Avalanches, falling rocks and ice, undermined snow, large glide cracks, and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains. We are no longer monitoring conditions in Huntington Ravine, but hazards will persist until all the snow and ice disappears.

High pressure will build into the region from Canada on Monday, keeping clear conditions until late in the week.  Temperatures during the days will reach into the 40sF and nighttime lows will drop into the 30sF. Low pressure will move into the area late in the week bringing unsettled weather. Our springtime isothermal snowpack has generally reduced avalanche concerns to sluff management in steep terrain.

The following hazards have all caused fatalities and should factor into your decision-making process:

  • Icefall: All visible ice will fall down at some point, often in large chunks that travel at high rates of speed. The most hazardous locations are in the center and looker’s right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur. Speed is safety when passing under any ice flow.
  • Glide Cracks and Waterfall Holes: As the snowpack gradually gives way to gravity, it pulls away from cliffs and leaves cracks that are most visible in extreme terrain, particularly the Lip. These glide cracks will grow larger and increase in number. The large waterfall hole in the Lip has spawned large and destructive wet slab avalanches in the past during times of heavy rain.
  • Undermined Snow: In addition to melting on the surface, the snowpack is eroded by running water beneath. This creates thin snow bridges that will collapse and are most prevalent in areas that have streams and at the tops of south-facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.
  • Long, Sliding Falls: Spring corn snow comes from the melt/freeze cycles on warm days and cold nights. The freeze portion of this cycle can turn a gully full of corn snow into an icy slope remarkably fast, possibly turning what would be a great ski descent into a down climb that requires crampons and an ice axe.

The Winter Lion Head Route is still open due to the amount of snow on the Summer Trail. The Sherburne Ski Trail is open down to crossover #7, allowing about ¾ mile of skiing below Hermit Lake.  Please respect the rope, cross over to the Tuckerman Ravine Trail, and hike down to Pinkham.

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  2:30pm., Sunday, May 6, 2018. A new bulletin will be issued when conditions warrant.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-06 General

General Bulletin for Huntington and Tuckerman Ravines

We are no longer issuing daily avalanche advisories this season for Tuckerman and Huntington Ravine. However, we will continue to provide snowpack and weather information for these areas when conditions change drastically and in time to help you make, or change, weekend plans. Avalanches, falling rocks and ice, undermined snow, large glide cracks, and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains.

Rain and possibly thunderstorms on Friday will set up a clearing pattern for Saturday. Temperatures close to the freezing mark to start Saturday combined with wind speeds over 100mph on the summit may make a late start the right choice as winds may drop to a more reasonable speed later in the afternoon. Rain on Sunday will be followed by what looks like a good corn cycle next week with sunny skies, warm days and colder nights. An isothermal snowpack has reduced the concerns for large avalanches, though history has shown that intense periods of heavy rain can make the waterfall hole in the Lip do strange things no matter what the snowpack is. Sluff management should be a priority for skiers, in particular the first several of the day on each slope.

The following hazards have all caused fatalities and should factor in when planning your route:

  • Icefall: All visible ice will fall down at some point, often in large chunks that travel at high rates of speed. The most hazardous locations are in the center and looker’s right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur.  Speed is safety when passing under any ice flow.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves cracks that are most visible in the extreme terrain, particularly the Lip. These glide cracks will grow larger and increase in number. The large waterfall hole in the Lip has spawned large and destructive wet slab avalanches in the past in times of heavy rain.
  • Undermined snow: In addition to melting on the surface, the snowpack is eroded by running water beneath. This creates thin snow bridges that will collapse and are most prevalent in areas that have streams (Little Headwall) and the tops of south-facing gullies. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard.
  • Long, sliding falls: Spring corn snow comes from the melt/freeze cycles on warm days and cold nights. The freeze portion of this cycle can turn a gully full of corn snow into sheet of concrete remarkably fast, turning what would be a great ski descent into a down climb that requires crampons and an ice axe.

The Winter Lion Head Route is still open due to the amount of snow on the Summer Trail. The Sherburne Ski Trail is open down to crossover #3, or where the rope is across the trail. Expect this closure to move uphill as the weekend progresses. Please respect the rope, cross over to the Tuckerman Ravine Trail, and hike down to Pinkham.

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  8:30 a.m., Friday, May 4, 2018. A new bulletin will be issued when conditions warrant.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-05-04

 

General Bulletin for Huntington and Tuckerman Ravines

We are no longer issuing daily avalanche advisories this season for Tuckerman and Huntington Ravine. However, we will continue to provide snowpack and weather information for these areas when conditions change drastically and in time to help you make, or change, weekend plans. Avalanches, falling rocks and ice, undermined snow, large glide cracks, and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains. Spring weather brings about rapid changes to the snowpack and presents objective hazards accordingly. Remember to ski, climb, or hike the snowpack and weather conditions that exist and not a date on the calendar!

This past weekend was a perfect reminder of how fickle spring weather can be. Saturday’s crowds were delighted by sunshine and abundant spring snow while those who ventured up to the Ravines on Sunday found rain and sleet at mid elevations and 11.1” of new snow on the summit. With light and variable winds, this snow likely blanketed higher terrain. Lingering instability in the atmosphere Monday will keep temperatures around the freezing mark for another 1-3” of snow and sleet on the summit. Building high pressure on Tuesday will create a clearing trend into Wednesday along with increasing wind speeds and temperatures. New snow from Sunday will experience rapid warming over the forecast period. Those venturing into avalanche terrain should be aware of the potential for wet avalanches. While wet-loose sluffs may be slow moving, this sort of “push avalanche” can easily take a skier over a cliff or into a glide crack. New snow will also cover developing holes in the snowpack, making safe navigation that much more difficult.

Remember to keep the following hazards in mind as you plan your route:

  • Icefall: Over the years many people have been severely injured or killed by falling ice in Tuckerman. The most hazardous locations are in the center and right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur.  Avoid spending time in the areas listed above and underneath any ice flows.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves gaps. These gaps are the horizontal cracks that will soon appear in the steep terrain, most noticeably in the Lip. These are deep enough to cause fatal injuries, especially around the main waterfall. This waterfall hole in the Lip is a unique hazard. In addition to creating a fall hazard, the flowing water has spawned large and destructive wet slab avalanches in the past.
  • Undermined snow: Meltwater flowing under the snowpack melts away the snow above, creating thin bridges of snow that can collapse. These are beginning to emerge at the tops of gullies (particularly on south-facing slopes) and in areas that have streams running, like the brook feeding the Little Headwall. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard. Breaking through weak snow into one of the larger water courses could be fatal if you become trapped.
  • Long, sliding falls: Part of what makes spring skiing so great is the melt/freeze cycle that creates stable, firm corn snow. The cycle begins when the snowpack freezes at night or in the afternoon shade on cooler days. This refreeze creates a hard surface on which it is nearly impossible to arrest a fall with skis or an ice axe. Refrozen snow can cause trouble for those looking to get “just one more run” at the end of the day.

While icy, the Winter Lion Head Route remains the preferred option for summit hikers due to the fall hazard at the traverse near treeline on the summer trail. Those who are summit bound should be on the lookout for this to change by the weekend. The lower section of the Sherburne Ski Trail is closed around the switchbacks of the Tuckerman Ravine trail, about ½ mile from the parking lot. Expect this closure to move up in elevation as temperatures skyrocket this week. In order to reduce erosion on the ski trail, please walk over to the Tuckerman Ravine Trail and hike the rest of the way to Pinkham Notch.

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, the Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.
• Posted  7:40 a.m., Monday, April 30, 2018. A new advisory will be issued when conditions warrant.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-

2018-04-30 General Bulletin

General Bulletin for Tuckerman and Huntington Ravines

We are no longer issuing daily avalanche advisories this season for Tuckerman and Huntington Ravine. However, we will continue to provide snowpack and weather information for these areas when conditions change drastically and in time to help you make, or change, weekend plans. Avalanches, falling rocks and ice, undermined snow, large glide cracks, and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains. Spring weather brings about rapid changes to the snowpack and presents objective hazards accordingly. Remember to ski, climb, or hike the snowpack and weather conditions that exist and not a date on the calendar!

Over two inches of rain and temperatures into the 40’s and 50’s over the past two days in the Ravines has consolidated the snow but has done little damage to the ski gullies in Tuckerman Ravine. A few lines such as the skier’s right fork of Hillman’s have shrunk into the barely skiable category but the Lip and most of the other main lines are still full with snow. Glide cracks are just beginning to emerge. Huntington’s ice climbs were damaged but still passable, though continued warm weather will make these increasingly sketchy due to undermining of the remaining ice and loose rocky topouts. The weather forecast is continuing to favor those with flexible work schedules and punish the 9-5ers. Rain will return Friday night and in the words of today’s MWObs forecaster “plague” the area through the weekend with rain shower activity. Warm temperatures remain in place through early Sunday which means flowing water and weak snow bridges will remain a problem especially in main watercourses. Periods of freezing temperatures may return briefly late Saturday night and more certainly Sunday afternoon and elevate the potential for slide-for-life conditions.

Remember to keep the following hazards in mind as you plan your route:

  • Icefall: Over the years many people have been severely injured or killed by falling ice in Tuckerman. The most hazardous locations are in the center and right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur. There is a lot of ice hanging on the cliffs in the Sluice and the Headwall. Avoid spending time in high risk areas like Lunch Rocks or on the floor of the ravine in the fall line of ice in the headwall.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves gaps. These gaps are the horizontal cracks that will soon appear in the steep terrain, most noticeably in the Lip. These are deep enough to cause fatal injuries, especially around the main waterfall. This waterfall hole in the Lip is a unique hazard. In addition to creating a fall hazard, the flowing water has spawned large and destructive wet slab avalanches in the past.
  • Undermined snow: Meltwater flowing under the snowpack melts away the snow above, creating thin bridges of snow that can collapse. These are beginning to emerge at the tops of gullies (particularly on south-facing slopes) and in areas that have streams running, like the brook feeding the Little Headwall. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard. Breaking through weak snow into one of the larger water courses could be fatal if you become trapped.
  • Long, sliding falls: Part of what makes spring skiing so great is the melt/freeze cycle that creates stable, firm corn snow. The cycle begins when the snowpack freezes at night or in the afternoon shade on cooler days. This refreeze creates a hard surface on which it is nearly impossible to arrest a fall with skis or an ice axe. Refrozen snow can cause trouble for those looking to get “just one more run” at the end of the day.

Though icy, the Winter Lion Head Route remains the preferred option for summit hikers due to the fall hazard at the traverse near treeline on the summer trail. The lower section of the Sherburne Ski Trail is closed around the switchbacks of the Tuckerman Ravine trail, about ½ mile or 400+ vertical feet from the parking lot. In order to reduce erosion on the ski trail, please walk over to the Tucks trail and hike the rest of the way to Pinkham Notch.

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 Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.
• Posted  8:00 a.m., Friday, April 27, 2018. A new advisory will be issued when conditions warrant.

Frank Carus, Lead Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-27 General Bulletin

General Bulletin for Tuckerman and Huntington Ravines

We are no longer issuing avalanche danger ratings for Tuckerman and Huntington Ravine this season. However, we will continue to provide snowpack and weather information two or three days per week for these areas. Avalanches, falling rocks and ice, undermined snow, large glide cracks and icy refrozen surfaces will remain a threat in and below steep terrain as long as snow remains in the mountains. Spring weather brings about rapid changes to the snowpack and changes objective hazards accordingly. Remember to ski, climb or hike the snowpack and weather conditions that exist and not a date on the calendar!

Yesterday, the temperature on the summit reached 43 F, with 62 F at Hermit Lake. Light wind from the southwest around 20 mph made it feel downright hot with sloppy snow conditions the result, particularly in strong solar aspects. Cloud cover moved in overnight and 1-1.5” of rain is forecast through Thursday. Temperatures all the way to the summit will remain mostly above freezing though they may dip down near freezing for short periods at the highest elevations. Snow or freezing rain may mix with rain at times but it doesn’t appear as if the snow will accumulate. The heavy rain and warm temperatures will speed the onset of spring hazards including the potential for large wet avalanches in limited areas, particularly the Lip. The recent warm, sunny days weakened the upper snowpack and threatened wet slab avalanches in a few areas though avalanches were limited to widespread but generally harmless wet loose sluffs. The heat also brought settlement as melt water percolated through the snow and rounded the existing snow grains. Continued warm temperatures with heavy rain will further saturate the snow and maintain the threat of natural avalanche activity in a few areas. Drier conditions and a return of freezing temperatures, possibly Saturday night, will improve stability and begin a corn snow cycle.

Remember to keep the following hazards in mind as you plan your route:

  • Icefall: Over the years many people have been severely injured or killed by falling ice in Tuckerman. The most hazardous locations are in the center and right side of the ravine, including Lunch Rocks, the Sluice, Lip, and Center Bowl. Warm weather and rain increase the potential for icefall to occur. There is a lot of ice hanging on the cliffs in the Sluice and the Headwall. Avoid spending time in high risk areas such as on the floor in the fall line of the headwall ice or at Lunch Rocks.
  • Glide cracks and waterfall holes: As the snowpack gradually gives way to gravity and creeps downhill, it pulls away from cliffs and leaves gaps. These gaps are the horizontal cracks that will soon appear in the steep terrain, most noticeably in the Lip. These can be surprisingly deep and are a place you don’t want to fall into. The waterfall hole in the Lip is a unique hazard. In addition to being a large hole, the flowing water has spawned large and destructive wet slab avalanches in the past.
  • Undermined snow: Meltwater flowing under the snowpack melts away the snow above, creating thin bridges of snow that can collapse. These are beginning to emerge the tops of gullies (particularly on south-facing slopes) and in areas that have streams running, like the Little Headwall. The sound of running water can sometimes be heard under the snow and is a good indicator of this hazard. Breaking through weak snow into one of the larger water courses could be fatal if you become trapped.
  • Long, sliding falls: Part of what makes spring skiing so great is the melt/freeze cycle that creates corn snow. The cycle begins when the snowpack freezes at night or in the afternoon shade on cooler days. The refreeze creates a hard surface that is nearly impossible to arrest a fall with skis or an ice axe. Refrozen snow can cause trouble for those looking to get “just one more run” at the end of the day.

Though icy, the Winter Lion Head Route remains the preferred option for summit hikers due to the fall and avalanche hazards at the traverse near treeline on the summer trail.

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 Mount Washington Volunteer Ski Patrol or the caretakers at Hermit Lake Shelters.
• Posted  8:00 a.m., Wednesday, April 25, 2018. A new advisory will be issued tomorrow.

Frank Carus, Lead Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-25 General Bulletin

Avalanche Advisory for Tuesday, April 24, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Yale, Central, Pinnacle, Odell and Escape Hatch have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE and LOW avalanche danger.  Right Gully, Sluice, Lip, Center Bowl, Chute, Lower Snowfields and Hillman’s Highway have Moderate avalanche danger.  Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall has undermining snow and open water.

AVALANCHE PROBLEM: Wet Slab is becoming our primary avalanche problem and will increase in likelihood with continued warming through the day. Wet slab avalanches are characterized by uncertainty, with the timing of peak instability for slab avalanches quite difficult to pin down. Our warming wind slabs that are becoming wet slabs also lend uncertainty to potential size of avalanches today, with large avalanches remaining a possibility. As surface slabs warm they may ultimately lose cohesion and be more likely to produce loose wet avalanches, or sluffs. Both of these avalanche problems will be most prevalent on sun exposed slopes. Areas receiving Low avalanche danger ratings today are rated so for limited potential size of avalanches.

In addition to avalanche concerns, spring hazards are emerging in the ravines. Icefall will be a key hazard resulting from today’s warm temperatures and solar heating. Areas under southerly facing ice, like Lunch Rocks, are particularly unwise places hang out. Melt water flowing under ice and potentially building up pressure will make ice dams a concern for climbers. Undermined snow will result from flowing melt water, with open holes and weak snow bridges over streams a potential concern in a number of locations including the Little Headwall.

 WEATHER: Yesterday finally felt like spring up here.  The summit hit a high of 34F with light and variable winds.  Overnight the temperatures only dropped to 30F with winds increasing to 40mph out of the W.  Yesterday Hermit Lake saw a high of 58F with light and variable winds.  Today we expect temperatures to stay slightly above average with a summit high around 40F.  The winds should increase slightly from yesterday to 25-40mph out of the W shifting to the SW.  This evening we expect unsettled weather to return which will bring precipitation that is currently predicted as an all-rain event.

SNOWPACK: Our upper snowpack consists of wind slabs formed late last week on a robust melt-freeze crust. These old wind slabs vary greatly in thickness, from several inches to several feet, and the older melt-freeze crust is exposed in some areas. Instabilities below this crust should not be of concern today. Wet slabs as an avalanche problem are characterized by uncertainty, and today is no exception. Instability will be primarily driven by warming of the upper snow pack.  This can weaken bonds between layers before the snow becomes truly wet, with melt water lubrication becoming a further cause of instability as warming continues. Surface slabs on southerly aspects may experience enough loss of cohesion though warming for loose-wet sluffs and point releases to become more likely than wet slabs, but again, uncertainty rules the day. Much of our terrain remained at or above freezing last night, furthering the warming of our snowpack. Skiing and riding should be best this morning and become increasingly sloppy and sticky as the day progresses. Where present at the surface, the old crust will be softened and likely provide the best turns. Wet slabs may be a tricky avalanche problem to manage, but the quality of skiing and riding generally deteriorates as instability increases on days like today. It’s a great day to get in and out of terrain relatively early, both to manage the avalanche problem and to score the best conditions.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t need an account to view them on your computer!

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.
• Posted  8:00 a.m., Tuesday, April 24, 2018. A new advisory will be issued tomorrow.

Ryan Matz/Amanda Tulip, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-4-24

Avalanche Advisory for Monday, April 23, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Yale, Central, Pinnacle, Odell, and Escape Hatch have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. North, Damnation, and South have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Right Gully, Sluice, Lip, Center Bowl, Chute, Hillman’s Highway, Lower Snowfields have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. Lobster Claw and Left Gully have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall is the exception with Low avalanche danger and areas of open water.

AVALANCHE PROBLEM: Wind slabs that formed over the weekend will still be our primary concern today. Warming yesterday may have allowed some additional bonding of these wind slabs to the icy bed surface.  While they appear similar, these slabs are variable depths across the terrain.  They proved firm and stubborn to human trigger yesterday however that doesn’t mean they are stable.  We would expect an avalanche today to be medium to large in size, particularly in Moderate rated terrain. Again today’s problem makes it a relatively low probability, high consequence day.  With the rising temperatures today spring hazards should being part of your travel decision making.  The forecast temperature and solar gain for today will help move us toward a traditional spring snowpack.  However, we have not reached this point yet so please continue to bring your avalanche gear and a mid-winter mindset.

 WEATHER: Yesterday the summit reached 20F while Hermit Lake reached 36F.  The wind stayed steady at 30 mph out of the NW with gusts reaching 50. High pressure has set up over the Northeast, with the center moving over us today.  This high will help decrease our winds to 10-25mph and shift them from NW to W.  It will also bring warmer air from the West and help us reach more seasonable April temperatures.  Today the summit should reach the mid 30 F and only drop to the upper 20’s F overnight. Tomorrow warmer temperatures continue with the high on the summit expected to reach 40F.  Cloud cover should increase late in the day with an incoming weather system.

 SNOWPACK: The up to 16” of snow and consistent loading wind speeds have created wind slab across much of our terrain. The bed surface is still the icy, hard crust formed from last week’s mixed precipitation and refreeze.  The slab varies greatly in depth from several inches to multiple feet.  The depth, along with the hardness, is hard to visually assess from the surface.  During observations yesterday we found 2’ thick layer wind slabs in close proximity to 2” of slab on top of a shallow graupel layer, illustrating current spatial variability. Bonding of the slab to the bed surface likely improved yesterday but not to the point of calling it stable.  With the warming temperatures and increasing solar gain today we expect peak instability to coincide with peak temperature. While sun should soften snow on the surface today, don’t expect an instant transition to corn snow from our late season wintry snowpack.  It is always a good idea to choose terrain appropriate to your preparedness and respect avalanche danger.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t need an account to view them on your computer!

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.
• Posted  8:10 a.m., Monday, April 23, 2018. A new advisory will be issued tomorrow.

Amanda Tulip, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-23

Avalanche Advisory for Sunday, April 22, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Yale, Central, Pinnacle, Odell, South and Escape Hatch have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. North and Damnation have Low avalanche danger. Watch for unstable snow on isolated terrain features.

 Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. Lobster Claw, Right Gully, Left Gully, Hillman’s Highway, and the Lower Snowfields have Moderate avalanche danger.  Evaluate snow and terrain carefully to identify features of concern. The Little Headwall is the exception with Low avalanche danger and areas of open water.

AVALANCHE PROBLEM: Wind slabs that formed since Friday are our primary avalanche problem. Of most concern today will be sun exposed areas holding largest slabs, like Sluice and Lip, where warming will push likelihood for human triggered avalanches toward likely and keep natural avalanches possible. Right Gully and Lobster Claw in Tuckerman and Yale Gully in Huntington should see similar affects though less capable of producing a truly large avalanche. We expect the somewhat firm wind slabs present in most of the terrain to be stubborn to a human trigger but capable of producing medium to large sized avalanches. This sets up a relatively low probability, high consequence day in which it’s plausible for the 5th or 10th skier, snowboarder, or climber rather than the 1st on a particular slope to trigger a large avalanche. Likelihood of triggering an avalanche will be slightly lower today than yesterday, but potential size of avalanches has not decreased, continuing to make the floor of Tuckerman Ravine an inappropriate place to linger.

 WEATHER: Temperatures below 20F on the summit and just above freezing at Hermit Lake yesterday paired with clearing skies and summit wind around 50 mph from the NW for a semi-pleasant day. Today is forecast to be approximately 10 degrees warmer with continued NW wind that should hold between 30 and 45 mph on the summit. Warmer temperatures and clear, sunny skies will make it feel spring like today and more so tomorrow, though the snowpack remains dynamic and more winter-like.

 SNOWPACK: Moisture from mixed precipitation earlier this week refroze and created a hard crust as a bed surface for the wind slabs which have formed since Friday. A few areas of this refrozen crust exist at the surface, but most of our terrain has been smoothed over by wind deposited snow. This means that the wind slab varies greatly in thickness from several inches to several feet, but it looks very similar from the surface. Layers do exist within this new wind slab, with a stiffer layer on the surface remaining reactive, but we would expect avalanches today to ultimately entrain all snow above the refrozen crust. Bonding in this upper snowpack has improved but not to the point of calling anything stable. Further, we expect stability to decrease with warming today, particularly on sunny aspects. A breakable sun crust from yesterday exists on some but not all southerly slopes, with inconsistent cloud cover suspected to be the culprit in variability of this crust. While sun today should soften this crust and affect stability, don’t expect an instant transition to corn snow from this wintry snowpack. Respect avalanche danger today by choosing terrain appropriate to your preparedness. Though avalanches may be less likely than yesterday, they could still be large. Bring your beacon, shovel, and probe along with an ability to use them as you carefully choose terrain. The Sherburne should ski well today and serve as an excellent consolation prize if today is not your day to travel in avalanche terrain.

Be sure to check out our Instagram posts (@mwacenter) for up to date photos and videos. You don’t need an account to view them on your computer!

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.
• Posted  7:40 a.m., Sunday, April 22, 2018. A new advisory will be issued tomorrow.

Ryan Matz, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-22

Avalanche Advisory for Saturday, April 21, 2018

Huntington Ravine has CONSIDERABLE avalanche danger. Yale, Central, Pinnacle, Odell, South, and Escape Hatch have Considerable avalanche danger. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. North and Damnation have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern.

Tuckerman Ravine has HIGH and CONSIDERABLE avalanche danger. Lip and Center Bowl have High avalanche danger. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. All other forecast areas have Considerable avalanche danger. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. The only exception to this is the Little Headwall which has Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern.

AVALANCHE PROBLEM: Recent new snow and steady NW wind is elevating the avalanche danger ratings today. Wind slab is likely to be easily triggered and is not bonded well to the soft new snow or the underlying ice crust. With over 16” of recorded snow on the summit since noon on Thursday, avalanches today could be large. Recent avalanche debris in Hillman’s and Dodge’s has been observed so far through the fog and blowing snow. These recent avalanches plus continued wind loading of slopes are obvious red flags for folks considering playing in or below steep terrain today. Well-developed avalanche paths exist, meaning an avalanche today could also run far onto flat ground. Entering the floor of Tuckerman Ravine today is not recommended as this will require crossing numerous avalanche paths that have the potential to avalanche naturally. With most of avalanche terrain offering a high-risk, high-consequence scenario, lower-angled terrain like the Sherburne will be the safe choice today.

WEATHER: Snow began to fall around noon on Thursday, April 19, and has been steadily accumulating, leaving 16.4” at the summit and 8.25” at Hermit Lake. Thursday evening, wind speeds increased to 40-60mph from the NW and have remained at that speed with occasional gusts into the 70mph range. The low pressure system sitting over the Northeast has begun to drift offshore and will allow clearing to take place later today. Before then, low level moisture will likely keep the summits in the fog with upslope snow showers for the morning. Temperatures today will climb to the upper teens F and winds will remain from the NW at 45-60mph.

SNOWPACK: The bed surface for avalanche activity today will be the ice crust that formed earlier this week. Below this ice crust, snow is still moist due to the insulating layer of snow above. Above this ice crust, widespread soft wind slab exists. This wind slab has several changes in density that are interspersed with graupel. Yesterday, this slab was reactive in stability tests, though struggled to propagate a crack. Continuing snow and wind loading today may allow the slab to overcome the minimal friction offered by the icy bed surface. Numerous red flags are present today; ski the snowpack, not the calendar.

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.
• Posted  8:00 a.m., Saturday, April 21, 2018. A new advisory will be issued tomorrow.

Helon Hoffer / Frank Carus, Snow Rangers
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-21

Avalanche Advisory for Friday, April 20, 2018

Huntington Ravine has CONSIDERABLE and MODERATE avalanche danger. Central Gully has Considerable avalanche danger. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. All other forecast areas have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern.

Tuckerman Ravine has CONSIDERABLE and MODERATE avalanche danger. Sluice, Lip, Center Bowl, and Chute have Considerable avalanche danger. Dangerous avalanche conditions exist. Careful snowpack evaluation, cautious route finding, and conservative decision making are essential. All other forecast areas have Moderate avalanche danger. Evaluate snow and terrain carefully to identify features of concern. The Little Headwall is no longer forecast due to open holes in the snowpack and is not recommended as an exit from the Bowl.

AVALANCHE PROBLEM: Six inches of new snow overnight arriving on increasing NW wind makes wind slab our avalanche concern today. No visibility this morning adds a degree of uncertainty to today’s forecast. We expect the snow to struggle to adhere to the ice crust which will act as today’s bed surface. This highlights a key characteristic about today’s avalanche problem; wind slab will likely be touchy to human triggers. In Moderate rated areas, the combination of wind and the slick bed surface may allow scouring to take place leaving areas of bed surface exposed. Considerable rated slopes, those in the lee of our fetch, should hold much larger areas of wind slab with limited to no old surface exposed. The potential for large avalanches exist in these areas with the possibility of natural avalanches due to continued loading through the day. The floor of Tuckerman Ravine today will be avalanche terrain as we have seen avalanches run far this year on well-developed slide paths. The hard bed surface will demand the use of crampons and an ice axe for those choosing to travel in avalanche terrain.

WEATHER: Low pressure centered over Nova Scotia will continue to send bands of winter weather to Mount Washington today. After a midday lull yesterday in wind speed combined with a spike in temperature to the mid-20s on the summit, snowfall began along with an increase in wind and a drop in temperature. Winds bottomed out at 5mph around noon yesterday and by midnight were above 40mph. As of this morning, the summit recorded 5.2” of snow while just under 6” fell at Hermit Lake. Today, temperatures will remain in the 20’s F in avalanche terrain with the summit reaching the upper teens. Winds should stay in the 40-55mph range from the NW. Snow is likely; 0.25” of SWE is forecast to arrive by this evening which could amount to another 2+” of snow. Wind and temperatures tonight should remain similar to today with another possible 2” of snow by tomorrow morning.

SNOWPACK: Over the past week, 10” of mixed precipitation arrived with a SWE of 3”. This was followed by cold temperatures that allowed a thick ice crust to form. On Wednesday, this crust was 4cm thick in places with moist snow beneath. With continued cold Thursday and last night, this crust will remain thick and strong, limiting avalanche concerns to the surface wind slab. We expect the new wind slab to vary in size from small to large depending on terrain and aspect. The uncertainty of wind slab size today comes from a combination of weather and snowpack factors compounded by no visibility. This same visibility challenge will make safe travel decision difficult today, as seeing avalanche start zones will be difficult. Days like today, which have a degree of uncertainty, are best for choosing low consequence terrain. The Sherburne will ski well today with top to bottom coverage.

Bear tracks were seen around the Fire Road and Tuckerman Ravine Trail. Please use the bear boxes and keep your camp clean if staying overnight at Hermit Lake. The Harvard Cabin is closed with no camping allowed anywhere on the east side of Mount Washington except at Hermit Lake Shelters or adjacent tentsites.

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.
• Posted  8:00 a.m., Friday, April 20, 2018. A new advisory will be issued tomorrow.

Helon Hoffer, Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-20

Avalanche Advisory for Thursday, April 19, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully has Moderate avalanche danger. 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.  Evaluate snow and terrain carefully to identify features of concern. All other forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall has open water in the steep section as well as the stream bed above. It is not a recommended route out of the Bowl.

AVALANCHE PROBLEM: Due to the rugged ice crust on the mountain, you’ll find two distinct threats to safe travelling in steep terrain. The recent sleet storm finished with freezing rain which created a thick ice crust over top of a widespread glaze of sleet, wet snow and ice. New snow fell at the end of the storm on Tuesday afternoon and was able to stick in some areas, but not very well. Due to scouring of the snow, wind exposed, scoured areas above tree-line will require crampons for safe travel while many lee areas have collected enough snow to build some wind slabs. Low visibility, and other duties kept us from gathering many observations yesterday and this morning, but it seems that the ice crust will be the dominant surface in steep terrain. In areas where the new snow adhered to the ice, hand shears low in Hillman’s Highway showed that the new wind slabs failed easily in the new snow. Only a small amount (2-3”) of the recent snow was light enough to be carried by the wind and blown into our terrain but the icy bed surface will up the ante if you get swept off your feet. Human triggered avalanches are unlikely today unless you seek out these areas of wind slab. Additionally, light winds may allow the 1-2” of new snow that falls to build into small but more sensitive, new wind slabs. If we receive the upper end of the forecast amount, human triggered avalanches will become more likely and increasingly widespread.

WEATHER: Just 0.7” of snow fell on the ice encrusted summit yesterday. This snow was light enough to be carried by the wind, like the inch or two which fell at the end of the storm on Monday and Tuesday. That storm brought a generous coating of sleet and ice totaling 10” of mixed frozen types and over 3” of water equivalent. A low pressure system will pass to the south today and spawn snow showers and some fog. Expect another wintry day with a high temperatures near 20F. Snow surfaces are unlikely to soften despite the warmish temperature and low wind speeds. More new snow toight and tomorrow may create more significant avalanche concerns tomorrow and Friday.

SNOWPACK: Instabilities in the snowpack are limited to recent snow. Yesterday, 8” or more of moist rounds were found beneath a rugged 3-4cm ice crust. This ice crust was more ice than crust and was just barely bootable on sub 20 degree slopes. Anything steeper required crampons or a stubborn desire to link skin-able sections of wind deposited snow. Lower on the mountain, the Sherburne was recoated with the sleet which has covered the bare spots on the trail that had begun to emerge. The trail is very skiable all the way to the parking lot at Pinkham Notch.

Bear tracks were seen around the Fire Road and Tuckerman Ravine trail. Please use the bear boxes and keep your camp clean if staying overnight at Hermit Lake. The Harvard Cabin is closed with no camping allowed anywhere on the east side of Mount Washington except at Hermit Lake Shelters or adjacent tentsites.

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.
• Posted  7:30 a.m., Thursday, April 19, 2018. A new advisory will be issued tomorrow.

Frank Carus, Lead Snow Ranger
USDA Forest Service
White Mountain National Forest
(603) 466-2713 TTY (603) 466-2856

2018-04-19