Avalanche Advisory for Wednesday, January 31, 2018

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall is not rated due to a lack of snow.  The Lip still contains a large void in the snowpack from the wet avalanche on January 12 or 13.

AVALANCHE PROBLEM: A firm and icy snowpack with some areas of mostly stubborn wind slab mark our terrain. These wind slabs are unlikely to produce an avalanche but are worth evaluating for signs of a weak bond to snow beneath and a tendency to sustain a crack along the surface. The wind slabs in question are easily visible and identified by contrast to the gray and dirtier looking, refrozen snow. You may find these slabs beneath steep pitches of ice and in other wind sheltered locations.

WEATHER: The temperature at Hermit Lake this morning is -2F and -10F on the summit with a NW wind in the low 60’s mph and gusting to 70 mph. Temps on the summit will warm to around 10F by nightfall as winds shift to the southwest. Wind speeds will diminish through mid-day before ramping up again as southwest flow brings clouds and light snow. Snow will start late in the day so is unlikely to create avalanche concerns though visibility may be reduced by snowfall and flat light. Scattered snow showers or light snow will continue through tomorrow and may refresh the snow coffers at higher elevations with up to 4-6” new snow by Friday morning. West winds combined with the new snow may create some unstable wind slabs tomorrow and Friday.

SNOWPACK: The dominant feature of the snowpack remains the widespread knife hard, ice glazed surface. Crampons are necessary to climb beyond low angle terrain due to this slick, hard surface. Stability tests and travel in Left Gully to the choke, about ¾ of the way up, last weekend showed that the older wind slab was well bonded to this icy surface. Nearer the surface, firmer (1F) wind slab over the thicker 4F slab created a clean shear at the interface between these two layers but neither layer showed any desire to propagate a crack much beyond your feet. No avalanche activity has been reported in these wind slabs. Elsewhere, the firm snow provides for quick and efficient cramponing but is an unforgivingly fast surface if you stumble so stay vigilant!

Microspikes and crampons are key tools for travel today. Crampons are needed on the steeper slopes and above treeline. Conditions on the Sherburne Ski Trail remain grim though passable for those desperate for a lap. Seems like the folks running to and from Hermit Lake and the summit yesterday had the right idea.

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 or Harvard Cabin.
• Posted 7:30 a.m., Wednesday, January 31, 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

2018-01-31

Avalanche Advisory for Tuesday, January 30, 2018

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. The Little Headwall is not rated due to a lack of snow.  The Lip still contains a large void in the snowpack from the wet avalanche on January 12 or 13.

AVALANCHE PROBLEM: A firm and icy snowpack with some areas of wind slab summarize our terrain right now.  The wind slabs that are out there are unlikely to produce an avalanche but are worth evaluating for signs of a weak bond to snow beneath or a tendency to sustain a crack along the surface. These wind slabs are easily visible and identified by contrast to the gray and dirtier looking, refrozen snow.

WEATHER: A fairly benign day is in store for the mountains.  High temperatures on the summits will be in the single digits with a steady northerly wind.   Some light snow may come through tonight with a better chance on Wednesday night, which may bring a couple of inches of replenishment.  While we can rejoice at the forecast of colder air at the onset of the weekend, significant snows are not looking to turn this icy rock around anytime soon.

SNOWPACK: The Ravines are dominated by a very hard icy surface with sporadically distributed wind slabs discussed in above.  These wind slabs have not proven to be very reactive during our stability tests   which generally showed that the wind slab was well bonded to this icy surface. Nearer the surface, firmer (1F) wind slab over the thicker 4F slab created a clean shear at the interface between these two layers but neither layer showed any desire to propagate a crack much beyond your feet. Snow and ice climbs are in great shape now and today’s calm weather and good visibility provide a good opportunity to enjoy them.  The firm snow allow for efficient cramponing but self-arrest must occur immediately if you slip, otherwise a long sliding fall will likely ensue.

Microspikes and crampons are key tools for travel today. Crampons are needed on the steeper slopes and above treeline. Conditions on the Sherburne Ski Trail remain grim though passable for those desperate for a lap.

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 or Harvard Cabin.
• Posted 6:15 a.m., Tuesday, January 30, 2018. A new advisory will be issued tomorrow.

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

2018_01_30

Huge thanks to volunteers Paul Bazanchuk, Ryan Brouder & Terran Siladi

Huge thanks to volunteers Paul Bazanchuk, Ryan Brouder & Terran Siladi for helping us with this battery bank/inverter setup donated by the Friends of Tuckerman Ravine. 

Avalanche Advisory for Monday, January 29, 2018

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features. Little Headwall has not refrozen completely and is far from filled in with snow so is not rated. The Lip still contains a large void in the snowpack from the wet avalanche on January 12 or 13.

AVALANCHE PROBLEM: A firm and icy snowpack with some areas of mostly stubborn wind slab mark our terrain. These wind slabs are unlikely to produce an avalanche but are worth evaluating for signs of a weak bond to snow beneath or a tendency to sustain a crack along the surface. The wind slabs in question are easily visible and identified by contrast to the gray and dirtier looking, refrozen snow.

WEATHER: It’s 15F at Hermit Lake this morning with calm winds, a few clouds and no precipitation recorded since January 24. Today, the summit will see partly cloudy conditions with a high of 13F and light winds in the 20-35 mph range. Summit fog is clearing this morning but high clouds will move in later today. Temperature and winds will remain mild and relatively calm today through Wednesday before shifting southwest as a bit of moisture arrives on Thursday. A better chance of more significant snowfall comes on Sunday.

SNOWPACK: The dominant feature of the snowpack in Tuckerman Ravine yesterday, in addition to the yard sale of refrigerator-sized blocks of ice from the wet avalanche, was the knife hard, ice glazed surface. Crampons were necessary to climb beyond the floor of Tuckerman Ravine due to this slick and hard surface with similar conditions in Huntington. Stability tests and travel in Left Gully to the choke, about ¾ of the way up, on Saturday showed that the older wind slab was well bonded to this icy surface. Nearer the surface, firmer (1F) wind slab over the thicker 4F slab created a clean shear at the interface between these two layers but neither layer showed any desire to propagate a crack much beyond your feet. Snow and ice climbs are in great shape now and looks as if we have a few days of calm weather and good visibility to enjoy them. The firm snow provides for quick and efficient cramponing but is an unforgivingly fast surface if you stumble so stay vigilant!

Microspikes and crampons are key tools for travel today. Crampons are needed on the steeper slopes and above treeline. Conditions on the Sherburne Ski Trail remain grim though passable for those desperate for a lap. Seems like the folks running to and from Hermit Lake and the summit yesterday had the right idea.

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 or Harvard Cabin.
• Posted 8:00 a.m., Monday, January 29, 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

2018-01-29

Avalanche Advisory for January 28, 2018

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully may rise to 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. All forecast areas may rise to Moderate avalanche danger today. Evaluate snow and terrain carefully. The exceptions to this rating are Lobster Claw, Right Gully and Lower Snowfields which have Low avalanche danger.  Watch for unstable snow on isolated terrain features there. Little Headwall has not refrozen completely and is far from filled in with snow. The Lip still contains a large void in the snowpack from the recent wet avalanche.

AVALANCHE PROBLEM: New wind slab may develop today if the mountain receives the upper end of forecast snowfall of a trace to two inches. The new snow could add stress to the scattered wind slabs that already exist in the terrain due to the inch or so that fell last night in higher terrain and blew into our forecast zones. Wind slabs scattered through these lee, sheltered areas may become sensitive to human triggering if the new snow forms more slabs on them. Yesterday, wind slabs showed no tendency to propagate a crack but additional snow load on top could make them more susceptible to human triggers. Evaluate snow carefully as you find your way through the terrain today.

WEATHER: Summit temperatures peaked at 28F late afternoon yesterday ahead of the passing cold front and have been steadily dropping. Current temperature on the summit is 21F and 30F at Hermit Lake. Expect temperatures to continue to decrease today with the summit reaching around 10F. West winds of 50 to 70 mph will moderate to 35 to 50 mph. Between lingering upslope snow showers and a secondary front passing this afternoon a trace to 2 inches of snow is possible.

SNOWPACK: The dominant feature of the snowpack in Tuckerman Ravine yesterday was the bullet hard, ice glazed surface. Crampons were necessary to climb beyond the floor of Tuckerman Ravine due to this slick and hard surface conditions with similar conditions reported in Huntington. Stability tests and travel in Left Gully to the choke showed that the older wind slab was well bonded to this icy surface. Nearer the surface, firmer (1F) wind slab over the thicker 4F slab created a clean shear at the interface between these two layers but neither layer showed any desire to propagate a crack much beyond your feet. These layers seemed to behave like the typical slabs that form here when legendary high winds and cold temperatures punish snow grains until they become complacent, lifeless rounds. Snow and ice climbing conditions have been stellar though today’s new snow may complicate route-finding.

Sharp edges, speed control and a willingness to sacrifice some P-tex to the snow gods is required to ski or ride the Sherburne Ski Trail today. Microspikes and crampons are key tools for travel today.

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 or Harvard Cabin.
• Posted 7:50 a.m., Sunday, January 28, 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

2018-01-28

Avalanche Advisory for Saturday, January 27, 2018

Huntington Ravine has LOW avalanche danger. All 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, Chute and Left Gully have 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.  The Little Headwall is mostly open water or waterfall ice and not rated.

AVALANCHE PROBLEM: Lingering wind slabs are the primary avalanche problem today. These slabs are poorly bonded to the icy, rock hard snowpack though are limited in size and distribution. Today, these areas of wind slab will warm for the first time and likely become more sensitive to human triggers as they weaken. Ultimately the heating will bring some stability to these slabs but not before passing through a period of less stability. Evaluate snow for signs of instability and bonding to bed surface, especially since even a small avalanche or fall can have serious consequences on our icy slopes. Larger areas of wind slab have a moderate rating due to the possibility of a human-triggered avalanche.

WEATHER:  A warming trend began last night with southwest flow and warming temperatures. After two days of below zero temperatures, the summit has reached 23F and will warm to the upper 20’s today before a cold front brings moisture to the area. It’s likely that our forecast area will see a mix of wet snow and rain. Less than an inch of snow and a tenth of an inch of rain will fall starting around dark. Temperatures will fall tonight with upslope snowfall continuing through the day tomorrow. WSW winds today will blow in the 40 mph range today, slowly ramping up through the day.

SNOWPACK:  December brought over 8’ of snow to the summit, but two warm rain events have reduced the snowpack to a mostly solid frozen mass with drainage channels in the surface, glide cracks and a slick icy surface. During field observations Wednesday, much of the snowpack was found to be a hard, refrozen snow from previous rain events, but with many pockets of wind slab varying in size and depth scattered around. These slabs were firm (finger to pencil) and poorly bonded to the ice crust below failing on a weak layer of snow (four finger) at the bed surface. It’s likely that the continued cold temperatures since that time only weakened this bond to the icy crust. Limited settlement may have occurred yesterday on aspects with strong solar gain but not enough to feel confident that human-triggered avalanches are now unlikely. The old gray, icy surface remains a safer place to evaluate the new snow as long as you’re wearing crampons, carrying an ice axe and moving carefully in the terrain.

The large wet avalanche in the Lip is slowly starting to fill in, but the hole in the snowpack and 20’ crown face is far from gone.  Skiing has been better this year for sure, but snow and ice climbs are in great shape. The Sherburne Ski Trail is a refrozen mess and best left for the most hardy and desperate of skiers.

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 7:20 a.m., Saturday, January 27, 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

2018-1-27

Avalanche Advisory for Friday, January 26, 2018

Huntington Ravine has LOW avalanche danger. All 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, Chute and Left Gully have 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.  The Little Headwall is mostly open water or waterfall ice and not rated.

AVALANCHE PROBLEM: The mountain received 2.5” of snow at the tail end of Tuesday’s low pressure system followed by strong winds from the west then north-west. Wind velocity was strong enough to scour the Alpine Garden above the ravines and deposit wind slab in our areas of concern. By and large, in good visibility, these wind slabs should not be difficult to avoid. In steep narrow gullies where route options are limited, venturing onto and triggering one of these slabs could result in a very nasty sliding fall on the icy bed surface. In the upper reaches of Left Gully and Chute, wind slab stretches wall to wall with no real option to avoid them. These wind slabs were poorly bonded to the ice crust beneath and sheared cleanly and easily. Be aware that low rated areas in our terrain may also be harboring these problematic wind slabs, though smaller in size with more options to avoid them altogether.

WEATHER:  Clear, cold and windy to start the day, with both temperature and wind hopefully moderating in the afternoon as the high pressure crests.  Current temperature at Hermit Lake is 3F and -9F on the summit.   Current summit wind is 62 mph from the NW.  Skies should remain clear for the forecast period with winds shifting west and diminishing to 20-35 mph by sunset. Summit temperatures will rise to the low teens.

SNOWPACK:  We had a great start to the season, but two warm rain events have reduced the snowpack to a mostly solid frozen mass. During field observations yesterday, it was clear that much of the snowpack is hard, refrozen snow from previous rain events, however there are many pockets of wind slab varying in size and depth scattered around. We found these slabs to be firm (finger to pencil) and poorly bonded to the ice crust below failing on a weak layer of snow (four finger) at the bed surface. It’s likely that cold temperatures overnight only weakened this bond to the icy crust.

The large wet avalanche in the Lip is slowly starting to fill in, but the hole in the snowpack and 20’ crown face is far from gone.  Skiing has been better this year for sure, but snow and ice climbs are in great shape. The Sherburne Ski Trail is a refrozen mess and best left for the most hardy and desperate of skiers.

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 7:15 a.m., Friday, January 26, 2018. A new advisory will be issued tomorrow.

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

2018-1-26

Avalanche Advisory for Thursday, January 25, 2018

Huntington Ravine has LOW avalanche danger. All forecast areas have Low avalanche danger. Watch for unstable snow on isolated terrain features.

Tuckerman Ravine has MODERATE and LOW avalanche danger. Lip, Center Bowl, Chute and Left Gully have 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.  The Little Headwall is mostly open water or waterfall ice and not rated.

AVALANCHE PROBLEM: Lingering wind slabs will be the primary avalanche problem today. Areas of mostly firm but potentially unstable wind slab exist in steep, lee terrain sheltered by recent NW winds. These slabs are on the smaller side but the consequences of an avalanche on our slick bed surface could be severe. Evaluate the snow carefully. Most of the terrain consists of a hard, gray old surface of refrozen, rain saturated snow. This is especially true in low rated zones where most of the 2.5” of snow which fell in the past 48 hours was scoured off of the terrain by high winds. Still, areas with a low rating may contain pockets of wind slab on isolated terrain features so assess these slabs for signs of instability or avoid them altogether. In Tuckerman Ravine, the run in the headwall known as The Lip contains an unusually nasty fall potential due to the 20’ crown face in the middle of the run. The affected area is in the fall line of the Tuckerman Ravine Trail making the consequences of a fall on this slope particularly dangerous. The refrozen and hard nature of the existing snowpack makes crampons, ice axe and microspikes useful, if not required, to safely climb any route that takes you above treeline.

WEATHER: Currently, the temperature at Hermit Lake is 3F and -6F on the summit with winds from the NW at 60 mph. Cold, dry conditions will persist today with below normal temperatures around -10F on the summit and NW wind increasing from 50-70 mph to the 65-85 mph range. Gusts could reach 100 mph. About an inch of snow was recorded early yesterday morning bringing the total snowfall recorded since the most recent rain to 2.5”. The next opportunity for snow appears to be Sunday when a low pressure system moves up the coast. Until then, count on dry but warming weather on Friday and Saturday.

SNOWPACK: Two warm spells with copious amounts of rain this month have turned our deeper snowpack into a rock hard mass. The large wet avalanche that blew out the waterfall in the Lip area is reforming ice but remains mostly unchanged with a large debris pile filling the floor of the Bowl. Snow and ice climbs in Huntington are in fine shape with plenty of water around to form new ice.

The Sherburne Ski Trail is rideable but barely concealed rocks and other rain damaged sections exist.

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 7:45 a.m., Thursday, January 25, 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

2018-1-25

 

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

2018-1-24

 

Avalanche Advisory for Tuesday, January 23, 2018

Huntington Ravine has LOW avalanche danger. Watch for unstable snow on isolated terrain features.

 Tuckerman Ravine has MODERATE and LOW avalanche danger. The Lip has 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 is mostly open water or frozen waterfall ice and is not rated.

Due to the open waterfall hole and a 20’ high avalanche crown line, the Tuckerman Ravine Trail is closed in the Ravine between Lunch Rocks and the Alpine Garden Trail. Please use the Winter Lion Head Route if going to the summit from Pinkham Notch. Other routes to the summit from the east side are more significant mountaineering challenges.

 AVALANCHE PROBLEM: The relatively small wind slabs built since late last week will become wet slabs as significant rainfall occurs today. Remember that triggering a small avalanche in consequential terrain can still have dire consequences. That said, natural and human triggered avalanches are unlikely today. The exception to these small slabs is “hang fire” in the area of the large avalanche crown in the Lip. Your primary concern in this location should be moisture and warm temperatures today that will decrease stability in the unsupported snow above the crown, which is currently a vertical wall of snow up to 20’ in height. Cautious travelers will avoid terrain under the Lip today for the high consequence of a large though unlikely avalanche from above this crown line.

 WEATHER: Up to 1” of new snow fell in our terrain overnight before warmer temperatures brought a change to wetter precipitation early this morning. It’s already above freezing at both Hermit Lake and the Summit. Summit temperature is forecast to hit the mid-30’s F today and not drop below freezing until after dark. By tonight rainfall will likely total approximately 1”. Moderate SW wind will shift W and increase late tonight as precipitation shifts back to snow. 2-4” of new snow is expected late tonight and early tomorrow morning and will taper off with decreasing cloud cover forecast for tomorrow as temperatures remain below freezing.

SNOWPACK: Small snowfall totals and the scouring and drifting effect of wind over the past week has left us with isolated pockets of wind slab over an exposed or thinly veiled crust. This crust formed over a week ago and is thick and very firm. The slide for life nature of a fall on this firm surface will decrease through the day as rain and above freezing temperatures soften surface snow, though a long sliding fall will likely remain possible. The unique hazard of concern today is an unlikely though potentially large avalanche from unsupported snow above the crown line of the massive wet snow avalanche out of the Lip that occurred last week. Rain and above freezing temperatures will weaken the previously frozen snow and a large avalanche could occur in this location. Spending time in the fall line of the Lip is not advisable for this reason.

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., Tuesday, January 23, 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

2018-1-23