Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:23a.m., Monday, January 31, 2011

Tuckerman Ravine: The Sluice, Lip, Center Bowl, and Hillman’s Highway have Considerable avalanche danger today. Natural avalanches are possible and human triggered avalanches are likely. The Lobster Claw, Right Gully, Chute, Left Gully and Lower Snowfields have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Little Headwall has Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine: All forecast areas have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The only exception to this rating is the Escape Hatch which has Low avalanche danger. Natural and human triggered avalanches are unlikely in this area.

I could get used to these clear blue sky mornings, but I don’t think I’ll ever get used to the -5F temperatures we currently have at Hermit Lake. The clear skies are providing ample visual clues as to what transpired in the ravines yesterday and overnight, and the morning sunshine is illuminating the plumes of blowing snow over areas such as Hillman’s Highway and the Lip. While the most significant loading and peak instability are probably behind us at this time, this morning’s 65mph (105kph) NW winds are providing sufficient wind loading to keep avalanche danger ratings elevated today. We do expect wind speeds to diminish slightly, but so far this morning they haven’t shown any signs of doing so. Additionally, cold temperatures will limit the amount of solar gain that can take place, so newly developed slabs will stay elastic, snappy, and reactive to additional loads. In Tuckerman, the areas of most concern are from the Sluice through the Center Bowl. A notable feature of this area is the absence of recent avalanche activity, as well as the low drifting snow that continues to pour down through these locations. Hillman’s also has a significant snow plume blowing over the top, which keeps the threat of natural avalanche activity present. On the northern side of Tuckerman, recent avalanche activity has helped remove some of the threatening snow from the gullies. With that said, understand that not every bit of unstable slab was cleaned out, and some reloading has occurred. These areas are at the upper end of the Moderate rating. Should you find yourself traveling in these areas you should expect new slabs to be reactive to human triggering.

Huntington Ravine also has a few “head’s up” locations, but on the whole this ravine presents a lesser avalanche danger than Tuckerman. We do believe it would be possible for you to trigger an avalanche in several locations, hence the Moderate rating. The bottom of South Gully, above the ice bulge in Central, and above the ice in Odell are just a few examples of where you can find potentially unstable snow. In the northern gullies it is the lower to middle sections that will pose the greatest threat.

A couple other noteworthy thoughts for this morning come to mind. First, the Escape Hatch and Little Headwall are both posted at Low avalanche danger. I personally don’t think either of these locations are quite ready to be used as descent routes. The Escape Hatch would be an epic bushwack, and the Little Headwall still has some open water and ice bulges. Remember, it’s still recovering from a 100% meltout at the start of January. Second, we have a hefty winter storm heading our way for Wednesday. I’ll go out on a limb and predict over a foot of snow, maybe 14-16″ by Thursday morning–but I’m not a meteorologist so don’t blame me when we only get a dusting! Hire the neighborhood kids to shovel your driveway and book your hotel room for Tuesday night so you don’t need to make the drive in the middle of the storm.

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 8:23a.m., Sunday, January 30, 2011

Tuckerman and Huntington ravines will have CONSIDERABLE avalanche danger today. Natural avalanches are possible and human-triggered avalanches are likely.  The only exception to this rating is the Little Headwall in Tuckerman which has Low avalanche danger.  Natural and human-triggered avalanches are unlikely in this area today.

This morning’s alpenglow was like a dream.  The tops of the ravines were ablaze in sunlight, barely a cloud was in the sky and the windless conditions made you forget that the mercury was still sitting below 0F at the summit.  Everything continues to appear so calm and peaceful but you just wait eight hours!  A passing disturbance has already started to cause the clouds to thicken and snow flurries to develop.  Maybe an inch (2.5cm) of new snow will fall before a trailing cold front pushes in and things begin to get interesting.  When this happens we’ll see an increase in winds as they blow out of the W at speeds up to 50mph (81kph).  These weather variables by themselves are probably leaving you scratching your head and wondering how the avalanche danger ratings have climbed in all areas today.  All you need to do in order to answer your own question is go kick around the Alpine Garden or Bigelow Lawn.  Since Thursday the Observatory has recorded just under 4” (10cm) of snow with an overall density of 3.1%.  Fluff like this isn’t very well designed for typical Mt Washington winds but the readings from the summit anemometer have been lower than normal since the low density snow began falling.  It hasn’t gusted over 50mph (81kph) since Thursday morning and yesterday’s average wind speed was a mere 13mph (21kph)!!!  During this period the blanket of champagne powder has lain waiting for the wind to set its travel plans in motion and today looks to be the day.  Wind-transported snow should begin to form soft slabs high in starting zones during the midday before higher speeds allow deposition farther down in the ravines late in the day.  Although they’re supposed to stay out of the W for the daylight hours you’ll want to keep an eye on their direction as a shift to the NW is expected this evening.  A shift to the NW would likely produce even greater levels of wind transport. 

Starting the day out we’re in a mix of Moderate and Low avalanche danger but expecting to climb the scale as we move into the second half of the day.  Windslab development will first take place atop unconsolidated light density snow thus creating the the “upside-down snowpack” that we are taught to keep an eye out for.  Because 3% snow has very little strength we expect to see small avalanches in many areas as winds ramp up.  After one avalanche cycle wraps up in an area I would expect reloading of the same slope to occur with development of thicker and more dangerous windslab. This is most likely in areas with E aspects such as the Center Bowl in Tucks and the gullies from Odell to Central in Huntington.  The areas on the periphery with N and S aspects will see cross-loading occur and we believe natural avalanches are possible late in the day.  Some of these areas like Huntington’s Escape Hatch are far less of a concern than say the top of Pinnacle but the snow densities and forecasted wind may still cause avalanche activity to occur.

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 8:05am, Saturday, January 29th, 2011

Tuckerman Ravine: The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.  The Lobster Claw, Right Gully, Left Gully, Hillman’s Highway, the Lower Snowfields, and Little Headwall have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

Huntington Ravine: All forecast areas have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas. Watch for unstable snow on isolated terrain features.

There are two key components to today’s advisory: first are the instabilities already out there, second are the ones that may be developing today. The existing instabilities, most notably in the areas of Tuckerman rated Moderate, are a result of a handful of light snowfalls over the past week combined with a variety of wind speeds and directions. The snow was able to load into well-protected areas such as under the ice in the Headwall, in parts of the lower Lip, and in the Chute. In these areas you can find energetic and reactive slabs interspersed with areas of snow that don’t give as much cause for alarm. To some degree, I believe solar gain early yesterday helped to stabilize slopes facing due S, but the farther around the Headwall you go toward the Chute, the less this would have happened. Using your skills to recognize potential instabilities and navigate around them can help you mitigate the avalanche hazard today. Of course, it is a Saturday, so you’ll want to be wary of potential human triggers that might be stomping around in your vicinity. Most of these areas of note are in parts of the Bowl that you can see from below, but clouds might limit visibility today and you still might need to contend with the second key component today–new slab development.

About 1.5″ (4cm) of very light density snow, generally 2-4%, fell yesterday and is continuing today. We might get around another inch (2.5cm) through the daylight hours as well. The winds are forecasted to be only 10-20mph (16-32kph) from the W. This is rather calm for Mt. Washington, but with snow densities being as light as they are it won’t take much of a gust to blow this snow in the direction of the ravines. Any new slab that is able to develop today will also be low density and soft. This is the type of slab that you might not recognize to be slab if you’ve only spent time in eastern mountains. It can be very soft and touchy, meaning that it doesn’t take much impact at all to initiate and propagate a fracture. Expect this development to take place in the upper elevations of the forecast areas, particularly those with an E-facing aspect.

Although I focused this discussion mostly on Tuckerman, the same factors are at play in Huntington Ravine. The biggest difference is that the overall size and distribution of existing slabs is small enough that they only qualify as isolated pockets of unstable snow, hence the Low rating. The problem related to developing soft slabs during the day may be taking place in Huntington, as well.

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 8:25am, Friday, January 28th, 2011

Tuckerman Ravine: The Lobster Claw, Right Gully, Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.  Left Gully, Hillman’s Highway, the Lower Snowfields, and Little Headwall have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

Huntington Ravine: All forecast areas have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas. Watch for unstable snow on isolated terrain features.

In the hours between 6am yesterday morning and 8pm last night, another half inch (1.25cm) of light density snow fell on Mt. Washington, bringing our 3-day “storm” total to 2.3″ (5.8cm). Our avalanche forecaster friends working in other mountain ranges would probably find this amount laughable. But here in the Presidential Range, small amounts of snow over several days are often “watch-out situations” for backcountry travelers. In Tuckerman, winds yesterday from the W, NW, and N pushed a consistent cascade of snow grains over the Headwall and into other lee areas on aspects facing E to S. This wind loading is continuing to fill in the nooks and crannies around the ravine, such as below old fracture lines, underneath the Headwall and Sluice ice cliffs, or into soft slabs up near the tops of Right Gully and Lobster Claw. For the time being, loading has shut down, which leaves the human trigger as the biggest cause for concern today. Particularly in areas rated Moderate, pay attention not only to what you’re doing but to what’s going on above you.

In Huntington Ravine, all areas today have dropped to Low avalanche danger. Most of the ravine has been rated Moderate for the past several days. You should be aware of the potential to find pockets of unstable snow on isolated terrain features in most of the gullies in Huntington today. These are isolated enough to drop the rating a notch, but that doesn’t mean you should go blindly charging up a gully any which way you please. Stay tuned into your avalanche awareness and you should be able to find reasonable routes to climb.

Increasing cloudiness and light snowfall is expected for the afternoon. Pay attention to how much snow falls during the waning daylight hours (or later, if you’re out after dark!) Winds during this time are expected to be from the W and rather light by local standards, which should keep new slab development to a minimum. Expect any new slabs created late today to be soft, tender, and located up in the tops of the gullies.

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 8:25am, Thursday January 27th, 2011

Tuckerman Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Little Headwall and Lower Snowfields which both have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

Huntington Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are North Gully, Damnation Gully, and the Escape Hatch which have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

We are in the middle of a series of weak weather disturbances that will present brief periods of clearing, dropping fog, and obscured summits over the next 2 or 3 days.  In addition to this some very light snow accumulations can be expected, which for each day should be minuscule, but has a tendency to make a difference over time.  Historically we’ve called this getting “nickel and dimed”.   My mom always told me every penny counts and I’m telling you the same in terms of snow accumulations.  The mountain has a way of saving up these small amounts waiting for a good wind event to load up some slopes, so although I don’t expect significant widespread instability we will likely be bumping along in the Moderate rating based on thin new slabs of concern.  This whole concept of light snow amounts jumps out at you if you look over January’s snow totals on the summit.  We are running at only about 66% of average for the month but it has snowed 21 out of 26 days.  Of these only 3 days were over 2” (5cm)!  Talk about a pittance from day to day but the pennies add up.  The other major point of these low snow amounts is the majority of them are upslope events caused in combination of energy and moisture in the valley with the orographic lifting of the mountains.  This usually happens under colder conditions which generates low density snow in the 4-7% water content range.  This is then easily transported by even light winds into touch soft slabs.

Bringing all this to today’s issues the summit picked up 1.4” (3.5cm) Tuesday and 0.4” (1cm) early this morning. Initially this precipitation came in on W winds from 50-65mph (80-105kph) 36 hours ago to a diminishing wind from all points on the compass rose over the past 24 hours.  This brought in some soft slabs mostly into E facing aspects and some minor cross loading of N and S facing slopes.  The top of Right Gully is an example of these S facing aspects.  One visual clue we’ve been watching is the fracture line from the Center Tuckerman Bowl avalanche on Saturday.  The crown continues to disappear, demonstrating that at least a foot an a half of new snow has been deposited near this area of the Ravine.  The new loading over the past 48 is layering over the very cold slabs we had in place from last week’s storm.  The cold weekend brought temperatures down to -35F (-37.5C) on the summit early Monday morning.  The slow warm up has started helping slabs, but our snow stakes near both Ravines are showing very limited settlement hinting consolidation is still at a crawl. 

The key points today are:

  1.  A skilled student of avalanche terrain travel with good stability assessment skills can find reasonable routes in both ravines if they pay attention to changing snow conditions and a high degree of variability. 
  2. You should expect new instabilities from the past 48 hours to be light in density and touchy to human triggers.
  3. A chance of new snow is forecasted for this afternoon and tomorrow on a building NW wind climbing to 55+ mph (88kph) by late today.  Expect this to bring in some additional light snow deposition high in the start zones of both Ravines.  

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

Print Friendly Avalanche Advisory PDF

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 7:33a.m., Wednesday, January 26, 2011

Tuckerman Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Little Headwall and Lower Snwofields which both have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

Huntington Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Escape Hatch, North and Damnation guillies have Low avalanche danger.  Natural and human-triggered avalanches are unlikely in these areas.

Yesterday’s rise to double digits above 0F felt downright balmy on the mountain even though we had snow showers for most of the day.  Not only was it good for the body and soul but it should have also been good for the snowpack. Unfortunately the stabilization of the lingering weaknesses in the upper layers of our snowpack has been slow to occur in the days since the mercury plummeted on Saturday. That morning we had a relatively large naturally-triggered avalanche in the Center Bowl of Tuckerman. The weakness on which this slab failed can still be found in both ravines with little change from that morning.  Another 1.4”(3.5cm) of light density snow blew in yesterday on W winds with ideal speeds for loading.  This created new windslab that has served as an insulating blanket to the cold snow below it.  As a result new snow has created new instabilities and helped to preserve those that already existed.  The primary areas of concern for new windslab are those with an E aspect.  Pinnacle, Central and Yale gullies have climbed up from yesterday’s Low rating and I would be concerned about new soft windslab in the starting zones of all three.  In Tuckerman Ravine most areas were rated Moderate yesterday but new snow pushes these areas farther up the continuum within that rating.  Dying winds make our concern for naturally-triggered slides take a far second to the potential for avalanches triggered by humans today. 

A chance for late day snow showers should be something to watch but we don’t feel like it will play a significant role in today’s stability. A greater chance for snow will move in tonight but what had once been hyped as a “storm” is now looking like it will only provide a few inches of snowfall. At least it will add the potential for more freshies on the Sherburne Ski 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 6:55a.m., Tuesday, January, 25, 2011

Tuckerman Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. The only exceptions to this rating are the Little Headwall and Lower Snowfields which both have Low avalanche danger. In these areas natural and human-triggered avalanches are unlikely.

In Huntington Ravine, Odell and South gullies have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. All other Huntington forecast areas have Low avalanche danger. In these areas natural and human-triggered avalanches are unlikely.

Can you feel it?  That’s right, the summit has pushed back above 0F(-18C) for the first time in three days.  Hurrah!  Snow showers have been recorded since midnight but little accumulation has occurred and no more than 1” (2.5cm) is expected over the course of the day.  Transport of this new snow will occur with today’s moderate W winds so E aspects should receive some direct loading while most other areas see some degree of cross-loading.  The windslab that develops as a result presents a new stability concern on top of the lingering issues of the past few days.  Arctic temperatures have allowed limited sintering of snow grains or dissipation of stored energy. Most stabilization has been put off until warmer temperatures creep down into the snowpack and allow these processes to resume.   Today’s forecasted ratings are identical to yesterday for this very reason.  Winds were successful at pushing old snow around early yesterday but this largely subsided by late morning.  The crown line from Saturday’s avalanche in the Center Bowl is still visible but watch for today’s W winds to try and bury it.

The areas of most concern in recent days have included the Lip and Sluice in Tuckerman, and in Huntington the approach to South Gully and the tops of Odell and Pinnacle. The areas that are still rated Low today may develop isolated pockets of new windslab in areas that are protected from W winds.  Due to the cold temperatures the density of falling snow should be very low.  This will allow transport at lower wind speeds and development of softer slabs that may be very reactive to a human trigger.  The tops of Central and Pinnacle gullies will be two spots to watch for isolated pockets of this type of snow.

We recently switched over to the Lion Head Winter Route for summiteers and you’ll want to make sure you have your crampons and ice ax in addition to all your cold weather gear. Extra goggles, mittens and heated underwear are all a good ideas as well.  A storm will be approaching the region tomorrow evening but at this time it looks like it will affect coastal areas more than the mountains.  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.

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 7:58a.m., Monday, January 24, 2011

Tuckerman Ravine has Moderate avalanche danger today. Natural avalanches are unlikely and human-triggered avalanches are possible. The only exceptions to this rating are the Little Headwall and Lower Snowfields which both have Low avalanche danger. In these areas natural and human-triggered avalanches are unlikely.

In Huntington Ravine, Odell and South gullies have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible. All other Huntington forecast areas have Low avalanche danger. In these areas natural and human-triggered avalanches are unlikely.

It’s been hyped up enough over the past few days and it’s finally here…the cold snap of 2011. Yesterday temperatures fell consistently into the night, hitting a low on the summit of -34F (-37C). All the while, winds speeds were blowing steadily in the 60-75mph (97-121kph) range with gusts into the eighties this morning (~130kph). These winds are currently moving some snow around Huntington and over the Headwall of Tuckerman Ravine, but the supply is limited and therefore so is the actual amount of loading going on. It can be mesmerizing to watch the snow cascading over the ice cliffs, but don’t let it lull you into blindly making travel decisions. Should you choose to brave the cold and enter into avalanche terrain there are some existing stability concerns to watch out for. These are mostly windslabs that have been sitting patiently for two days now, unable to move in the direction of stabilization. The cold temperatures and brisk winds have been preventing the dissipation of elastic potential energy, which is one way slabs can stabilize over time when it’s not quite so cold.  Spatial variability will add some diversity to the avalanche potential from one forecast area to another, as well as within each forecast area. Some of the areas of most concern include under the Lip and Sluice in Tuckerman, and in Huntington on the approach to South Gully and in the tops of Odell and Pinnacle. There is a variety of surface conditions out there from old surface to soft windslab. When you’re selecting your route try and utilize the harder surfaces to keep your impact bulb from extending too deeply in the snowpack.

We recently switched over to the Lion Head Winter Route for summiteers and you’ll want to make sure you have your crampons and ice ax in addition to all your cold weather gear. It’s time now to start hyping the next weather event. Look for some sort of storm heading our way for Wednesday night. As usual, computer models are taking their time to come into consensus on how this will affect us; at this time it seems worth paying attention to, at least.

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 7:50a.m., Sunday, January 23, 2011

Tuckerman Ravine has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.  The only exceptions to this rating are the Little Headwall and Lower Snowfields which both have Low avalanche danger.  In these areas natural and human-triggered avalanches are unlikely.

In Huntington Ravine, Odell and South gullies have Moderate avalanche danger. Natural avalanches are unlikely and human-triggered avalanches are possible.  All other Huntington forecast areas have Low avalanche danger.  In these areas natural and human-triggered avalanches are unlikely.

We started off yesterday by watching a natural avalanche pull out of the Center Bowl while we were putting together the advisory.  More than one person asked why we didn’t rate all areas as High yesterday if we witnessed natural activity.  There are quite a few things that go into the ratings but it’s important to remember that naturally-triggered avalanches may occur under any rating.  Under a Moderate rating like we have in most areas today, natural avalanches may still occur though they are considered unlikely.  It may seem like semantics but the definitions for each rating are far more important to understand than just the single rating word alone. The arctic air mass currently in place has allowed little stabilization to occur since yesterday but diminished winds have removed much of the concern for natural activity.  Under the Moderate rating human-triggered avalanches are possible and this will be the main focus today.  At the end of yesterday we watched a party of six boot down through the Lip in an area not far from the morning’s avalanche in the Bowl.  They may have been more confident going through there than I would have but they had everyone in their group on the slope at one time.  Had an avalanche occurred they would have likely all been buried.  Remember your safe travel rules!!!

There is a variety of surface conditions out there from old surface to soft windslab.  When you’re selecting your route try and utilize the harder surfaces to keep your impact bulb from extending too deeply in the snowpack.  Some areas such as Left Gully and much of Huntington allow you to avoid most of the questionable snow but isolated pockets of windslab and hangfire from the last avalanche cycle should keep you on your toes.   The tops of some areas like Yale and Pinnacle have pockets worthy of note while in other areas the concerns are much lower down. Though the frigid temperatures will keep the crowds to a minimum today it is a weekend and you’ll still want to keep an eye out for two-legged triggers wandering the slopes above you.  Temperatures will continue to fall and reach -35F (-37C) tonight.  Winds will ramp back up out of the NW today with forecasted speeds of 60+mph (97+kph).  To say it’s cold is an understatement.

We recently switched over to the Lion Head Winter Route for summiteers and you’ll want to make sure you have your crampons and ice ax in addition to all your cold weather gear.  The Sherburne Ski Trail is open top to bottom with ungroomed backcountry goodness.

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 Ravine

Posted 8:55a.m., Saturday, January 22, 2011

Tuckerman Ravine: Lobster Claw, Right Gully, the Sluice, the Lip, Center Bowl, and Chute all have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Left Gully and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. The Lower Snowfields and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.

Huntington Ravine: Central, Pinnacle, Odell, and South gullies have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger today. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

Throw an extra pair of long underwear in your pack, it’s going to get chilly this weekend. A cold snap will take hold today and last through Tuesday. Summit temperatures are potentially going to be colder than they have been in four years. Add reasonably strong winds and you’ll be facing some very challenging conditions over the next few days. Know all your options in advance so you don’t need to spend unnecessary time above treeline figuring things out. Enough about that, let’s get on to the avalanche discussion…

Yesterday the winds on the mountain shifted to the WNW and began to ramp up steadily through the afternoon and evening. They peaked at 101mph (162kph) from the W before coming down to their current speeds in the 60mph (97kph) range. This transported plenty of snow into Tuckerman Ravine, which set off a round of avalanches in numerous areas, followed by more loading that happened after the maximum wind speeds had been reached. As if the mountain wanted to show that it means business today, it just released a pretty good sized avalanche in the Center Bowl as I was writing this advisory! One of the first things taught in most avalanche classes is the idea that recent avalanche activity is a red flag indicating unstable snow. With natural avalanche activity taking place before our eyes, it’s not at all a stretch to say that the snowpack might be a little sensitive today. Cold temperatures tend to keep the elastic energy in the slabs, which allows fractures to propagate through them. The areas rated Considerable harbor the most unstable snow, due to continued reloading since the last avalanche cycle. As loading subsides with further diminished wind speeds this afternoon, the threat of naturally triggered avalanches will decrease as well, but the potential for human triggered slides will remain elevated thanks to the cold temperatures and snappy slabs. Left Gully has a stepped crown line below the narrows, with sufficient hangfire to warrant a Moderate rating. Obedience to safe travel rules is a must for anyone entering avalanche terrain today, including just going to the floor of the ravine for a look around.

In Huntington there is a mix of Moderate and Low danger. The winds created a variable snowpack, with the Moderate rated areas having some scouring, but more areas where reloading took place after any avalanche activity occurred. Human triggered avalanches are possible here. In the areas posted at Low, you’ll need to be watchful for unstable pockets. One example is the top of the fan below Yale Gully, but anywhere you find deeper slabs on steep terrain you should be watchful.

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

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