Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:00 Wednesday, December 29, 2010

Tuckerman Ravine: The Sluice, Lip, Center Headwall and Chute have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  All other forecast areas in Tuckerman Ravine have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  The Lower Snowfields and Little Headwall are not posted due to a lack of snow in these areas.

Huntington Ravine: All forecast areas in Huntington Ravine have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  The Escape Hatch is  not posted due to a lack of snow in this forecast area.

After several exciting and exhausting days of intense storm conditions from a powerful Nor’easter, things are beginning to improve.  In fact, by the end of the week we may be watching the thermometers rise to record temperatures for the New Year.  I know many of you have been patiently waiting for the mountain to relax a bit and today is providing you with the most reasonable opportunity to get out and enjoy winter since the storm began on Sunday night.  Before charging into the Ravines, take a deep breath and ponder the avalanche danger.  This recent storm brought around a foot and half of new snow (40 cm) with winds beginning out of the NE and working their way to the NW on Monday.  Winds remained out of the NW yesterday with strong gusts reaching over 100 mph (161 kph).  Brief breaks in the clouds yesterday afternoon allowed us to observe that (to no surprise) avalanche activity had occurred in both Ravines.  Clouds didn’t pull back enough to reveal the entire story and this morning we are greeted with a thick cloud bank that is preventing us from seeing the Ravines.  We have rated most forecast areas Moderate due to the potential of people triggering slabs deposited over the past couple of days.  Due to the strong wind speeds, I expect to find areas scoured down to old surface or very hard wind slab in a number of places.  I also expect to find some unnerving wind slab that could avalanche if it is irritated by the additional load of a person.  We hope to sort this distribution out today if the weather cooperates.  The areas in Tuckerman Ravine that are posted Considerable are the places that are the most likely to produce natural avalanches.  Today’s winds are forecasted to remain out of the NW with speeds between 35 and 60 mph (56 and 97 kph).  These winds may continue to move snow into sheltered areas and create new and potentially unstable wind slabs.  While some reasonable options may exist for traveling in avalanche terrain, it will require skill in the art of route finding and assessing snow stability to manage the conditions safely.  Also be mindful of what is going on above you.  If you are in the clouds you won’t be able to see if wind loading is continuing or if another party is crossing a suspect slope while you are in the run-out.

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 the Harvard Cabin.
  • This advisory expires at midnight. 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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:46a.m., Tuesday, December 28, 2010

Tuckerman Ravine has High and Considerable avalanche danger. Huntington Ravine has Considerable avalanche danger. The Sluice, Lip, Center Bowl and Chute have High avalanche danger.  In these areas natural avalanches are likely and human-triggered avalanches are very likely.  Travel in avalanche terrain is not recommended.  All other forecast areas have Considerable avalanche danger.  Natural avalanches are possible in these areas and human-triggered avalanches are likely.  We have not begun forecasting for the Little Headwall, Lower Snowfields or Escape Hatch due to a general lack of snow.  Forecasting  will begin in these areas when conditions warrant although avalanche activity may occur prior to this point.

Things are happening on Mt Washington!  Our trip up the trail this morning included chainsaw work for fallen trees that had been snapped by strong winds.  We also observed heavy drifting along the trail while other areas were scoured down to old surface.  These clues provide insight into what may be happening behind the clouds of blowing snow that conceal both ravines.  As a quick recap we picked up more snow than was expected from the Nor’easter but strong winds made exact measurements impossible.  Between measurements at our snow plots, along the trails and down at Pinkham it appears that we received somewhere around 18” (45cm) of 8-10% snow.  The Observatory recorded less than that but it’s difficult to determine how accurate their measurements were in the hurricane force winds.  Reports from around the White Mountain region confirm high variability in snowfall amounts from a 5″ (13cm)  in the Conway area to more than two feet (60cm) in Randolph and Crawford Notch.  Winds throughout the snow event have been in excess of 50mph (81kph) with recent observations at the summit pushing toward today’s forecasted speeds of 100mph (161kph).  The winds initially blew out of the NE but later swung through the N during yesterday’s snowfall before ending up in the NW where they are expected to stay through tomorrow.  This drift across the compass allowed all areas to pick up wind-transported snow through direct and cross-loading activity.  Avalanche activity and high winds have likely cleaned new snow out of some areas and restarted their loading cycle multiple times.  Poor visibility is preventing us from getting much visual data from the ravines and blowing snow will likely continue to problem through the day.  Nonetheless, the Observatory is continuing to report blowing snow and increasing winds will keep moving the snow from the NW side of the mountain up and over to Tuckerman and Huntington ravines.

Arctic cold continues to dominate the weather pattern today with a current temperature on the summit of -8F(-22C).  With winds pushing 100 mph and snow to fill the air, a trip above treeline today is asking for trouble.  Yesterday we had an incident with a hypothermic patient at Hermit Lake.  The weather is nasty out there and you’ll need to bring lots of extra equipment to ensure a proper margin of safety.  It should be assumed that all trails except for the Tucks Trail are unbroken and heavily drifted.  Snowshoes or skis will be necessary to navigate off of any packed 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 caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:10a.m., Monday, December 27, 2010

Tuckerman and Huntington Ravines have High avalanche danger today. Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended.

The gift giving season may be over, but that didn’t stop Mother Nature from delivering a belated blast of winter weather. The National Weather Service has issued a BLIZZARD WARNING for much of New Hampshire, including Mt. Washington, until 3pm today. This will make for very dangerous avalanche conditions, so traveling into avalanche terrain today is not recommended. It’ll be best to wait this one out before heading for steep slopes or the runouts below them. I could stop right here and you’ll know all the information you really need to know to travel safely today. However, for snow-starved winter enthusiasts, the details are exciting enough to warrant a full discussion.

On the ground at Pinkham there is already more snow than we expected to see by the end of the day. With the wind whipping it all around it’s difficult to measure exactly, but I’d venture a guess of 14” of low density fluff has fallen so far. Snow will continue to fall during the day while winds will slowly walk their way around from the NE to the NW. Wind speeds today have the potential to exceed the 100mph mark (160kph) as well. This will not only send all the new snow into the avalanche terrain, but also will have the strength to pick up any old snow that had been sitting above treeline waiting for an event like this to transport it into the ravines. I expect the avalanche cycles have already begun, with multiple avalanches still to come during the day.

Ok, so you’re not heading into avalanche terrain but you still want to get out in the mountains? Remember to bring plenty of good quality gear suitable for blizzard conditions. Drifting will be significant everywhere, so some sort of floatation may not be a bad idea, either. In addition to blowing snow, temperatures will plummet today as cold air gets brought in from the north.

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:40a.m., Sunday, December 26, 2010

Tuckerman and Huntington Ravines have both LOW and MODERATE avalanche danger today. Natural and human triggered avalanches are unlikely in areas posted at Low and natural avalanches are unlikely and human triggered avalanches are possible for areas posted Moderate.  We have not begun forecasting for the Escape Hatch, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

Tuckerman: Hillman’s Highway, Left Gully, Chute, and Center Bowl have Low avalanche danger.   The Lip, Sluice, Right Gully, and the Lobster Claw have Moderate avalanche danger.

Huntington: South, Odell, Pinnacle, and Central have Low avalanche danger.  Yale, Damnation and North have Moderate avalanche danger.

Temperatures from the teens to mid twenties F over the past 2-3 days are allowing some slow changes in our snowpack towards a stabilizing trend, but not quite enough to drop any forecast ratings from Moderate to Low.  The start zones of southern aspects that were loaded Thursday into Friday morning still harbor the instability issues of most concern.  Slopes with southern aspects like the climbers right side of the Lip, the Sluice, Right Gully, Lobster Claw, Yale and Damnation and North continue to have softer slabs than areas with other aspects posted at Low.   In much of both Ravines outside of these south facing slopes, anchors and the broken nature of snowfields are assisting most slabs to remain in place, but as you move through a patchwork of snow, bushes, rock and ice re-evaluate slab stability constantly.  Due to spatial variability, particularly across the Center Bowl in Tuckerman, expect changes in slab quality and strength.

The big news on the horizon is we are in a WINTER STORM WARNING beginning later today through Monday.  Some showers may begin in the mountains during daylight hours, but the real onslaught is expected to start after dark.  Expect blizzard like arctic conditions with very limited visibility making above treeline travel tonight and tomorrow quite severe and not recommended.  I would consider planning today’s mountain adventure such that you do not end up benighted; a little conservatism would be prudent.  The general trend is for temperatures to drop allowing colder lower density snow to fall while wind will begin from the ENE/NE and walk over to the NW and increase to a freight train roar.  8-12” (20-30cm) are expected with localized higher amounts.  The initial problems and potential for natural avalanche activity will be on south aspects because of direct loading from the NE and N and terrain protected east slopes due to cross loading.  By daybreak tomorrow we should be gusting to 100mph (160kph) as we move from the N to the NW.  Northwesterly winds should directly affect the majority of our avalanche terrain, loading aspects not as influenced by the earlier NE direction. Summit temperatures should drop about 20 degrees F from the current of 15F (-10C) to -5F (-21C) tomorrow.  All of this should translate into multiple cold dry snow avalanche cycles tonight and tomorrow if accumulation predictions and winds play out.  Century winds have not been seen in a long time on Mount Washington so I would expect a fair amount of snow currently sitting above treeline to be moved into the Ravines along with new snowfall.  I would anticipate elevated avalanche danger ratings tomorrow likely hovering around “High” for many areas.  Powerful winds should also do their fair share of scouring in addition to avalanche creation.  As always, it will be very important to read the avalanche advisory over the next couple of days as you may see rapid increases, and perhaps decreases, in avalanche potential.

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 9:15 a.m., Saturday, December 25, 2010

MERRY CHRISTMAS FROM THE SNOW RANGERS!

Tuckerman and Huntington Ravines have both LOW and MODERATE avalanche danger today.  Natural and human triggered avalanches are unlikely in areas posted at Low and natural avalanches are unlikely and human triggered avalanches are possible for areas posted Moderate.  We have not begun forecasting for the Escape Hatch, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

Tuckerman: Hillman’s Highway, Left Gully, Chute, and Center Bowl have Low avalanche danger.   The Lip, Sluice, Right Gully, and the Lobster Claw have Moderate avalanche danger.

Huntington: South, Odell, Pinnacle, and Central have Low avalanche danger.  Yale, Damnation and North have Moderate avalanche danger.  

Very little has changed in the past 24 hours and much of the discussion from yesterday pertains to today.  The summit received no new snow since Friday morning, but the Ravines saw some very minor loading when winds shifted to the NE around 11am yesterday.  We witnessed this while in Tuckerman assessing conditions and saw snow plumes over the Sluice, Right Gully and the Lobster Claw.  You might find a small new pocket or two high in some start zones, but these didn’t amount to much due to moderate winds and a wind shift back towards the N.   A number of areas forecasted at Low have stability issues just below what I would consider the appropriate criteria to be listed at Moderate.  Although they are posted at Low realize they aren’t the rock solid conditions we can see with very high winds or very cold temps after a rain event.   Anchors and the broken nature of many snowfields are assisting some slabs to remain in place, but as you move through a patchwork of snow, bushes, rock and ice re-evaluate slab stability constantly.  Due to the spatial variability across areas like the Center Bowl in Tuckerman expect changes in slab quality and strength.  Slopes with southern aspects like the climbers right side of the Lip, the Sluice, Right Gully, Lobster Claw, Yale and Damnation and North have softer slabs in the strong lee protected from N winds than areas with other aspects posted at Low.   

The biggest impact of the snow accumulations this week is a such more hike friendly Tucks trail from Pinkham to Hermit Lake.  It isn’t often I’m more excited about snow on the trail than snow in the Ravines but the water ice development on the first 1.5 miles from the parking lot was close to record breaking.  We thank all the mountain travellers that packed new snow on top of the ice before it all blew away!  The trail has gone from “crampons or die” to “ski poles would be helpful” conditions so although there is an icy patch or two they are fairly insignificant. 

Some snow is poised to move in for perhaps later tomorrow.  Timing and toals are a bit unclear depending on track but we will discuss it in Sunday mornings advisory.  Have a great Holiday Weekend!  

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

Christopher Joosen, Snow Ranger
USDA Forest Service

Printer Friendly Avalanche Advisory PDF

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 9:23a.m., Friday December 24, 2010

Tuckerman and Huntington Ravines have both LOW and MODERATE avalanche danger today.  Natural and human triggered avalanches are unlikely in areas posted at Low and natural avalanches are unlikely and human triggered avalanches are possible for areas posted Moderate.  We have not begun forecasting for the Escape Hatch, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

Tuckerman: Hillman’s Highway, Left Gully, Chute, and Center Bowl have Low avalanche danger.   The Lip, Sluice, Right Gully, and the Lobster Claw have Moderate avalanche danger.

Huntington: South, Odell, Pinnacle, and Central have Low avalanche danger.  Yale, Damnation and North have Moderate avalanche danger.  

After a number of days of cloudy upslope snow conditions we finally have a beautiful morning on Mount Washington with outstanding visibility.  Yesterday’s projected wind speeds fell quite short of expectations and therefore we have a different snow stability situation today than I was anticipating yesterday.  Winds were forecasted to gust to 80 mph, but only reached a peak velocity of 54 mph.  This is still a respectable speed but had the forecast come to fruition we believe a lot of snow that had been sitting above treeline had the potential to scour off and load into the Ravines.  With all that said our nickel and diming precipitation accumulations are adding up and snowfields continue to grow.  Over the past 4 days the summit received 11” (28cm) of snow with moderate northerly winds.  Occasionally wind direction vacillated a bit but most loading came in from pretty close to true N.  This has left a number of south facing aspects less wind effected and loaded with more new slab than many other aspects that were either wind packed or scoured in most instances.  A number of areas forecasted at Low have stability issues just below what I would consider the appropriate criteria to be listed at Moderate.  Although they are posted at Low realize they aren’t the rock solid no-brainer we can see with very high winds or very cold temps after a rain event.   As discussed yesterday anchors and the broken nature of many snowfields are assisting some slabs to remain in place, but as you move through a patchwork of snow, bushes, rock and ice re-evaluate slab stability constantly.  Due to the spatial variability across areas like the Center Bowl in Tuckerman expect changes in slab quality and strength.  Slopes with southern aspects like the climbers right side of the Lip, the Sluice, Right Gully, Lobster Claw, Yale and Damnation and North have softer slabs in the strong lee protected from N winds than areas posted at Low.  We will spend some time in the field this morning taking a closer look at some of our problem areas and discuss anything we find in the Christmas advisory.  We will start the Weekend Updater next Friday which will occur each week through May 2011.  Have a great Holiday Weekend and if you’re still desperate looking for the perfect gift for your mountain obsessed love one order up an avalanche beacon and throw in an airbag for good measure.

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printer Friendly Avalanche Advisory PDF

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:25a.m., Thursday December 23, 2010

Tuckerman and Huntington Ravines have Considerable avalanche danger today.  Natural avalanches are possible and human triggered avalanches are likely.  Note that we have begun forecasting for the Lobster Claw today and is included in the Tuckerman rating.  We have not begun forecasting for the Escape Hatch, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

It’s not as obvious as a 2 foot dump with big winds, but today is certainly a period with avalanche potential on Mount Washington.  Higher elevations picked up a bit over 4” (10cm) of snow as of midnight and it continues to fall.  This adds up to over 8” (20cm) for the past three days associated with a predominately N to NNW wind.   Maximum wind speeds have nudged just a bit higher each day with this afternoon seeing a substantial increase in velocities.  The Mount Washington Observatory and the NWS expect gust potential between 70 and 80 mph (112-128kph) later today with additional snowfall potential between 2-4” (5-10cm). 

These weather conditions will continue the mountain’s increasing avalanche trend pushing towards the upper end of the Considerable rating later this afternoon.  The snow accumulations and expected winds would typically have us thinking about a High rating during a normal late December-January date. However, the amount of anchors in the form of rocks, turf, and vegetation still plague a number of areas making snowfields smaller and less contiguous than the average mid winter day.  These issues will, in a few areas, assist some slabs from failure (a.k.a. avalanching), but this anchoring should not occur everywhere especially aspects with S, SE, and even E facing components which will see substantial loading during today’s daylight hours.  Tuckerman’s Right Gully, Lip, and Center Bowl under the headwall ice are some examples of areas to consider avoiding.  Remember to evaluate certain gullies with a multiple aspect start zone carefully. Left gully is an example of a classic broad bowl-like top having a very steep south facing wall that will receive direct loading today from N winds even though much of the gully faces E and NE.  Everything points to a heads up day and to put it most simply, we could possibly see some natural avalanche activity that is larger than anything seen thus far in the 2010-2011 season.   

Clear weather is expected to move in tomorrow and for Christmas Saturday.  We are excited to see what this latest round of weather and potential avalanche activity has done to the terrain.  We will relay anything we find right here at www.mountwashingtonavalanchecenter.org.  Check back and stay tuned.   

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printer Version Avalanche Advisory PDF

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:34 a.m., Wednesday, December 22, 2010

Tuckerman and Huntington Ravines currently have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  We have not begun forecasting for the Escape Hatch, Lobster Claw, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

In our forecaster’s meeting this morning we had a good discussion of the current issues effecting avalanches that had us going back and forth between a mostly “moderate” situation or trending towards “considerable”.  We decided that moderate best reflects today’s stability with a few caveats.  Yesterday morning we reached a peak wind speed of 62mph (100kph) on the summit from a northerly direction, which was the highest velocity in quite some time.  We anticipate this moved Monday’s 2” of snow and the past several days of modest accumulations before that into a number of southerly aspects.  However, some weather forecasts were calling for a NW wind which historically gives us greater instabilities than what actually occurred from the N, hence the “Considerable” forecast.  This NW direction did not come to fruition so a number of areas were struggling to meet Tuesday’s rating and likely spent the day sitting in the “Moderate” range. 

This morning’s weather report is very similar to yesterday.  We picked up another 2” up high as of midnight with a northerly wind currently blowing at about 30mph (48kph).  Winds are expected to pick up later today approaching 50+mph (80kph).  This should be associated with an additional 1-2” of snow which will put us on an increasing avalanche trend.  Generally, we would be most concerned about aspects in the direct lee of the current and expected winds.  Today this would mean slopes pointing towards the south.  Right now our southerly facing slopes and gullies are still a bit boney nevertheless they do have enough snow to act as a base layer for avalanche activity.  But these snow patches are not nearly as large or continuous as they will become later this winter.  South facing start zones in Huntington’s Yale, Damnation, and North gullies as well as Tuckerman’s Right Gully and the Lobster Claw are still small and broken up by rocks and bushes in many places.  So although it is important to recognize these locations as the primary locales for new loading we have more concern for some of our more well developed aspects.  Tuckerman’s Sluice, Lip, Chute, Left Gully and Huntington’s Central have larger snowfields and are more cause for concern than the aforementioned southern aspects.  Left Gully and the Chute sit almost perpendicular to today’s wind and usually see some cross-loading as well as scouring with moderate winds.  Although close in compass direction to these, the more protected Center Bowl and Lip should see greater snow instabilities and they stand out for us as the main areas to be concerned about.  Light snow densities coupled with modest winds should allow the development of scattered soft slab that may be reactive and touchy.  As the day progresses be aware that avalanche danger is on an increasing trend allowing a number of open slopes with a south to easterly aspect to move towards the upper end of the Moderate range.  As we move into tonight additional snow and winds will have the ratings hedging toward the Considerable definition.     

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:45a.m., Tuesday, December 21, 2010

Tuckerman and Huntington Ravines have Considerable avalanche danger today.  Natural avalanches are possible and human triggered avalanches are likely.  We have not begun forecasting for the Escape Hatch, Lobster Claw, Lower Snowfields, or Little Headwall due to a general lack of snow in these areas.  Forecasting will begin for these areas when conditions warrant although avalanche activity may occur before this point.

 Well it finally feels like winter and guess what?  It is!  We all wanted to see last night’s lunar eclipse but if it wasn’t possible I’d personally settle for a little low density powder to ring in the winter.  Snow began falling yesterday around sunset and by midnight the summit had picked up 2.2” (5.5cm) of 6% light density fluff.  Another 2-4” (5-10cm) is expected over the course of the day today.  Winds remained out of the N at around 35mph (56kph) for much of the evening but this was plenty fast enough to send the snow flying.  As the day moves along we expect to see an increase in speed as the Observatory is forecasting winds up to 65mph (105kph) with higher gusts. 

One of the more critical pieces of information that seems a little more difficult to pin down today is the wind direction as we feel the lingering effects of the storm that recently passed us a little too far to the E.  The Observatory’s summit forecast calls for NNE winds today while the National Weather Service is expecting them to come from the NW.  It may not seem like a big deal but the combination of topography above the ravines (Bigelow Lawn and Alpine Garden), forecast area aspect, and existing bed surfaces make this an important piece of information.  NW winds tend to deliver much more snow to the ravines than those from the N or NE. If we were better able to pin down the direction we might be able to drop some forecast areas down to the Moderate rating.  I would expect areas with a southerly aspect to reach the Considerable rating well before other areas make the jump today.  These include the Right Gully, Sluice and Lip in Tuckerman and Yale, Damnation and North in Huntington.  Soft and touchy windslab will likely develop over unconsolidated low-density snow in these lee areas where protection from the wind is highest.  This layering will cover what had been at the surface—a mixture of compacted snow/neve with scattered areas of faceting.  Areas that have an easterly or northerly aspect will still pick up snow but this will be mostly through cross-loading.  Instability issues will be slower to develop in these spots but the layering described does not lend itself well to stabilization.   If you’re out in avalanche terrain today it will be essential to exercise careful snowpack evaluation, cautious route-finding and conservative decision-making.

 The lower sections of the Tuckerman Ravine Trail have been an icy nightmare and have made all of the Snow Rangers firm believers in lightweight traction footwear.  I rarely wear crampons below Hermit Lake but some of the past days have made me wish that I had ten big spikes on each foot and maybe even a couple of ice tools to run laps on some of the crazy ice flows that have developed off the sides.  Long, nasty sliding falls are possible in a few areas and some snow on top will make these hard to detect.  Be careful out there or you’ll end up broken and tossed in the woods somewhere along the way!

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 the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:00a.m., Monday, December 20, 2010

Tuckerman and Huntington Ravines have Low avalanche danger.  Avalanches are unlikely but you should watch for unstable snow on isolated terrain features.  We are not currently forecasting for the Little Headwall, Lower Snowfields, Lobster Claw, or Escape Hatch due to an overall lack of snow in these areas.

This past weekend provided favorable conditions for visiting mountaineers.  A lack of wind made the cold temperatures reasonable and snow stability was good in most areas.  As a result we saw lots of climbers and even a handful of skiers who weren’t afraid to take on the scrappy early season conditions.  A number of avalanche courses were out this weekend poking around and many of the students noted the development of faceted snow.  These facets have developed as the result of high temperature gradients within our relatively thin snowpack.  Facets are currently number one on the stability watch list as their square crystal shape lends itself well to the creation of a persistent weak layer.  Although all areas are posted at Low avalanche danger today you’ll want to watch for locations where cohesive windslab covers this loose sugary snow.  As of this morning these areas of concern can be classified as isolated pockets but you can bet that we’ll be watching how near-surface facets interface with new snow.  An inch or so (2.5cm) of snow is expected overnight and winds are forecasted to finally pick back up.  They shouldn’t find too much snow available for transport until around midnight when they’re expected to push to 50mph (80kph) out of the N to NE.  If the winds crank up earlier than forecasted an alarm should go off in your head as blowing snow is one of several red flags of instability. 

If you plan on heading up the Tuckerman Ravine Trail from Pinkham Notch you should be prepared for about a mile and a half of low angle mixed climbing with long sections of water ice blanketing the entire trail.  The lower part of the trail is quite challenging without crampons or other traction footwear and there is the potential to take a nasty fall.  Over the past couple days we have noticed blood-stained ice and the tracks of sliding bodies where people’s skill and equipment didn’t match the conditions.  Leave a little extra time and energy to navigate this section of 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 caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

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