Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:30a.m., Friday, February 18th, 2011

Tuckerman Ravine has CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. The only exception to this rating is the Little Headwall which has Low avalanche danger. Natural and human triggered avalanches are unlikely.

All forecast areas of Huntington Ravine have MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

The key factor for snow stability in the ravines today is free water in the snowpack. Temperatures in the ravines have been hovering in the 35-40F (2-5C) range for more than 24 hours now. This is causing the snowpack to melt away, and as this happens the water has to go someplace. Wet slabs can be fickle beasts, and knowing exactly how much water is needed to weaken a slab to the point of fracture and failure is more or less impossible. You’ve got to rely on the factors you can measure or observe, and make educated decisions from there. In this case, we know the temperatures in the ravines have been above freezing for a period of time, and we know that prior to the warm-up there were existing wind slabs with underlying layers that ranged from facets under eroding crusts to wind-hammered hard slabs. Today’s weather forecast leads me to believe temperatures will be warmer today than yesterday, and remain above freezing at the ravine elevations until sometime after dark. Free water will continue to percolate into the snowpack until we move below freezing later tonight. The combination of all these factors leads to the conclusion that natural avalanche activity is possible in Tuckerman Ravine. In Huntington Ravine, the weather factors will be the same as in Tuckerman, the difference between the two is predominantly related to the existence of slabs prior to the warm-up. Huntington had less new surface slabs and much more wind-hammered surfaces. The bump up to Moderate today reflects the continued application of heat to the snowpack and the increase in size and distribution of potential avalanches that goes along with it. In other words, although naturally triggered avalanches remain unlikely, you can expect avalanche danger to be relatively greater than what you’d find under a Low rating. Furthermore with Huntington, you’ll want to pay attention to the increased potential for falling rock and ice. Wet slabs being what they are, I would not recommend relying too heavily on snowpit stability test results as an indicator of stability today.

The upcoming weekend is a holiday weekend, and the following week is a school vacation week. These are two factors that typically combine to put lots of people out and about in the mountains. If you’re going to be one of them, be sure to check the latest weather forecasts before heading above treeline or the latest advisory before heading into avalanche terrain. Tonight I expect temperatures to drop well below freezing, which will turn much of the water-logged snowpack into something akin to polished concrete, particularly in steep terrain. In other terrain, such as down lower in the flats or in transitions from flat to steep, you might find nasty breakable crusts in one location and rock solid hardpack a few feet away. Winds tomorrow will be raging on the mountain, and a little bit of snow can be expected. If you’re thinking of doing a run on a backcountry ski trail, consider sharpening your edges or else bringing along a full set of hockey pads; it’ll be challenging conditions after it all freezes solid. All in all it’s going to be a tough day in the mountains tomorrow. We’ll get into more detail tonight in the Weekend Update section of our website.

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 8:58, Thursday, February 17th, 2011

Tuckerman Ravine has both CONSIDERABLE and MODERATE avalanche danger.  The Sluice, Lip, Center Bowl and the Chute have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely. All other forecast areas have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Huntington Ravine has LOW avalanche danger.  Natural and human triggered avalanches are unlikely except in isolated terrain features or extreme terrain. 

The mid winter thaw has begun!  The positive thing I can say is this thaw should be brief and not all that damaging to the mountain snowpack, but nevertheless heat and rain is never fun in winter.  Driving up to Pinkham Notch this morning it was 12F (-11C) for a good part of my commute.  An hour later at Hermit Lake it is 40F (4.5C)!    Air mixing from the valley and up high should slow this rapid spike of mercury at the mid elevations however these temperatures will impact cold slabs today setting us on an instability trend over the next 24 to 36 hours.

Brian and I got into Tuckerman to see the effects of Tuesday’s big wind and snow.  A sizable debris pile littered the floor with many very hard and icy chunks of hard slab as well as pieces of water ice, insinuating that the avalanche cycle stepped down into older hard slab.  The mass and force impacted even deeper slabs causing them to fracture but not fail leaving behind a number of large “settlement cracks” some of which appear like crevasses.  They were impressive and larger that I have seen in a long time.  Check out a couple of the pictures posted yesterday on our website.  We both felt this event would have produced a sizable crown line but not a piece of it could be seen as continued loading filled in the evidence.  We believe the majority of the debris came from the right side of the Headwall near the Lip over to the Sluice.  While examining all of this we poked around under Right Gully and the Lobster Claw and found plenty of cold facets beneath an eroding crust.  In numerous locations this crust was at the surface and in others it was beneath slabs of varying thickness.  We have been chasing and watching facets in different stages since the crust development a number of storms ago as cold conditions have prevailed over the past few weeks.  This is the underlying cause for concern in this warm up.  As slabs warm they will lose their tensile strength that is currently allowing them to bridge these varying pockets of facets.  By affecting the temperature gradient in the snowpack, slab thickness over the crust has affected the development, size and relative weakness of these facets from snowpit to snowpit. Therefore, expect a high degree of spatial variability due to pockets of advanced facets under quite different thicknesses of slab.  The instability will increase through the day as heat penetrates cold slabs, with areas reaching Considerable this afternoon and areas rated Moderate to reach into the upper end of the rating.    The Sluice should be the first to reach Considerable today, due to its south facing aspect and the soft slabs I encountered yesterday.  In summary, we have gone to a Considerable rating in the Sluice, Lip, Center Bowl, and Chute mostly due to the potential for natural avalanche activity due to weakening slabs over areas of advanced facets as we move through this warm weather and rain potential.

In Huntington Ravine the avalanche danger rating is posted at Low today.  We believe natural avalanches are unlikely, but not impossible to occur over the next 24-48 hours.  The definition for “Low” avalanche danger allows for avalanches to occur in isolated terrain features and/or extreme terrain which most of Huntington’s steep gullies qualify.  Also anticipate some falling ice to cause an additional hazard.

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

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:15a.m., Wednesday, February 16, 2011

Tuckerman Ravine has Low and Moderate avalanche danger today. The Lower Snowfields and the Little Headwall have Low avalanche danger. Natural and human-triggered avalanches are unlikely.  Watch for unstable snow in isolated terrain features.  All other forecast areas in Tuckerman Ravine have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

Huntington Ravine has Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

Today is a pleasant contrast from yesterday’s punishing weather.  Bitter cold temperatures paired with raging winds that gusted over 100 mph (161 kph) for hours on the Summit made most people’s flight instinct take over and head for the valley.  Recent snow was being whipped around through the early afternoon resulting in new wind slabs in most forecast areas in Tuckerman Ravine.  As expected, the snow was unable to find a suitable landing zone in the gullies in Huntington and they are now stripped down to older snow layers.  As a result there are numerous options for climbing  and today’s relatively mild conditions will allow for an enjoyable experience.  In Tuckerman there are a wide variety of snow conditions to be found that fall within the Moderate rating.  Some areas, like Left Gully and Hillman’s Highway, can be managed safely with good route finding techniques that avoid newer wind deposited snow.  Others, like the Center Bowl, Lip and Sluice, will leave you no option but to travel on the new wind slabs.  These areas are well connected and if a fracture in the snow was initiated, the resulting avalanche could be fairly sizable.  This is an experience I would not recommend.  Expect slab hardness to vary as you move around.  Softer cohesive wind slabs will be easier to trigger than the dominant hard slab that requires you to kick in hard to gain traction in places.  Expect to find the softest snow down low including in the sheltered areas of the Lower Snowfields and around the Little Headwall.  These two forecast areas are not well developed yet but you may find some isolated areas of instability, particularly on the north side of the Lower Snowfields toward the Little Headwall.

A warming trend will be the topic of discussion in the coming advisories.  Warm air making its way into the region could topple tomorrow’s Summit record temperature of 34 F (1C).  This warm air will stick around until Saturday.  Our field observations will be focusing on the current stability of the wind slabs discussed above as well as analyzing how this warm weather will effect them.  Depending on what we find out there, you may see an increase in the avalanche danger as a result of the warming trend.  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.

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 8:30a.m., Tuesday, February 15, 2011

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

Huntington Ravine has Low avalanche danger. Natural and human-triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

Our relationship with the mountain is love-hate in so many ways.  Yesterday she decided to show us a little Valentine’s Day sweetness by not developing another crust layer as you will now find at most lower elevations.  The warmest air of the day came in the morning as we were working on the advisory but the mercury soon dropped just enough to allow the ravines to move back below the freezing mark.  When precipitation moved in during the late afternoon there was a hint of liquid in the air but it soon changed to graupel and then straight snow.  The summit picked up 1.7″ (4.3cm) of new 6% snow while we measured around 4″ (10cm) at both the Hermit Lake and Harvard Cabin snowplots.  The measurements are somewhat questionable based on the amount of wind effect we’re seeing and the Tucks Trail was heavily drifted in this morning.  On the other hand my gut was telling me that we received more snow than the summit reported so 4″ might be accurate. Not getting rain in the ravines was great but additional new snow really reminded us of why we fell in love with this rockpile.

Then there’s the wind…the hateful, punishing wind.  While it blew out of the W for the majority of the day yesterday it eventually made the wrap to the NW after dark and began to blow with the fury of a lover who got the boot on Valentine’s Day.  Speeds have already pushed over 100mph (161kph) this morning and are forecasted to gust upwards of 120mph (193kph) as the day moves along.  These conditions have likely scoured many areas including the majority of Huntington Ravine hence the Low rating.  Despite this rating we expect that you will find isolated pockets of new hard windslab in Huntington especially in well protected areas such as the lower portions of the gullies  and upper part of the Fan.  In Tuckerman the wind direction and speed have likely caused some scouring where terrain features squeeze the wind through constrictions such as upper part of Left Gully.  Historically this happens to a far lesser degree than it does in Huntington.  With a couple inches of new snow (if not more) combined with what existed from days past I expect that we have developed widespread hard windslab in Tuckerman’s forecast areas.  We’ve seen some high winds over the past week but nothing quite as strong as today and they’ve mostly been out of the W.  The higher speeds with a NW origin will allow snow to be ripped up from alpine areas where it was formerly safe.  As it is deposited in Tuckerman Ravine it is being laid down on top of existing layers of windslab that have caused ratings to be elevated for the past week.  Some of the areas in the direct lee of today’s winds such as the Lip haven’t seen a Low rating since January!  With all this in mind we expect to see natural avalanche activity occur today in Tuckerman Ravine and believe that new cold windslab will be reactive to human triggers.

Today’s arctic temps will allow potential energy to remain in the new snow.  They’ll also remind you that the mountain often shows no love for her suitors.  It is currently -18F (-28C) at the summit with winds gusting over 115 mph (185kph).  If you’re planning on a summit bid today I’d recommend staying in the valley and going shopping for all the leftover, half-price chocolates.  The mountain won’t miss you.

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 8:15a.m., Monday, February 14, 2011

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

Huntington Ravine: Central Gully has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas of Huntington have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

For all you snow lovers out there, this Valentine’s Day isn’t going to be the kind of day you fantasize about, but avalanche conditions are interesting enough that you might want to peel off a couple layers and admire the snowpack. Just don’t bring flowers; that would be a little weird. Like yesterday, there are a couple of concerns for you to watch for. First are the existing instabilities, some of these are older and becoming less of a concern over time and some of these are more recent. Yesterday, 1.7″ (4.3cm) of snow fell on the summit while winds blew generally from the W at 50-70mph. This new snow is the cause of Central Gully being bumped up one rating from where it was yesterday. In other areas of Huntington you might want to watch for any isolated instabilities, particularly in sheltered lee areas. Around Tuckerman you’ll find slabs of varying ages and hardnesses. Some of the oldest ones that still hold avalanche potential are in the Sluice, Lip, and Center Bowl. On top of the older, harder slabs is some newer snow that’s blown in, but for the most part this takes a back seat to the aforementioned slabs in these areas. In other areas, such as Hillman’s, you’ll find sections with relatively softer slabs. Field tests yesterday had these failing within the slab itself, rather than at an interface between two distinct layers. Good stability can be found in some areas of Tuckerman by searching out the snow that got pounded into submission by strong winds. You’ll find this in much of the Lobster Claw, Right Gully, and Left Gully.

The second concern today is related to the incoming weather. Today will be a warm day for sure. It’s already above freezing here at Hermit Lake and summit temperatures are forecasted to reach into the lower 20’s Fahrenheit. New snow is forecasted for the afternoon and evening hours as well. I’m hopefully that temperatures will stay low enough at our elevation that any new precipitation falls as snow. By the end of the day we might see an inch or maybe two, which, when blown in on strong W winds (50-70mph/80-113kph) will have the ability to create new slabs or build on existing ones. Watch what the weather is doing today. Look for indicators such as snow starting earlier or heavier than expected, or if those droplets hitting your face are actually rain and not snow, these should tell you that avalanche danger may soon be on the rise.

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 8:15a.m., Sunday, February 13, 2011

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

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

Yesterday’s snow showers deposited just over an inch of new snow at the Hermit Lake snow plot.    Winds on the Summit increased out of the west through the day with gusts over 100 mph (161 kph) late last night.  Even though these winds did not have much new snow to work with, they were determined to make the most out of it.  This effort resulted in several small natural avalanches that occurred in the Chute, Center Bowl, Lip and Sluice in Tuckerman.  These areas are the most protected from west winds and were able to offer a place for the wind blown snow to collect.  Areas that are not as protected had their scant amounts of new snow swept away by the strong winds.  Huntington Ravine is pretty well scoured out as is Left Gully in Tuckerman Ravine.  For today, there are three snow stability issues to be on the lookout for.  The first is any new wind slab deposited by yesterday’s weather that did not avalanche. These slabs are going to be relatively thin and could be easy to trigger.  You will find them in very sheltered areas of west winds.  Based on the size of the recent avalanches that occurred in Tuckerman, I would expect new avalanches that occur in the new snow to be  pretty small.  The second stability issue is wind slab that is left over from last week. These have been responsible for keeping some forecast areas in Tuckerman at Moderate for a while now.  The good news is that these slabs are likely to be difficult to trigger based on their high density and the fact that they have been around for several days and have had some time to settle.  The bad new is that if you are able to get one go it could be a sizable slide that you wouldn’t want to be in.  Examples of these slabs can be found in Hillman’s Highway and in the Center Bowl, Lip and Sluice.  The third snow stability issue you need to be aware of today is incoming weather that may increase avalanche danger in all forecast areas by the end of the day. Low pressure will turn our blue bird day into clouds and snow with 1-2″ (2.5 to 5 cm) of accumulation forecasted by the end of the day.  West winds between 50 and 75 mph (80 and 120 kph) will be transporting this snow into the Ravines and new wind slabs will begin to develop.  This is similar to what happened yesterday but the winds aren’t going to be as strong.  This will allow new slabs to develop in many areas and could start to become problematic by the end of the day.  Light snow will continue overnight and tomorrow with a total of 2-4″ (5 to 10 cm) expected by the end of tomorrow.  As a result, expect elevated avalanche danger tomorrow.

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 8:10a.m., Saturday, February 12, 2011

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

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

Avalanche conditions in the ravines today are similar to where they’ve been for the past couple days, with a couple of areas’ ratings dropping from Moderate to Low and a little bit of weather coming in toward the end of the day that might push things back up the scale again. For the better part of the day conditions will remain where they currently are; however, we are expecting up to an inch of new snow along with strong W winds, particularly in the late afternoon. Depending on exactly how much new snow falls, this may increase the avalanche danger in many of the areas currently rated at Low. So before we get into what’s currently out there, take the idea of changing conditions and stash it in the back of your mind so that if you’re out later in the day when conditions begin to change you won’t get caught unaware.

Both ravines feature a dominant surface layer that is leftover from very strong winds midweek. Tuesday night wind gusts exceeded 100mph and they stayed strong in the following days. This left a lot of wind-hammered slab in many places. This hard slab has a great deal of strength to it, and in general it’s strongest in locations that are thickest and hardest. The locations that didn’t feel the full force of the winds are the ones where the slabs that built are softer, and these relatively softer slabs are also relatively weaker and hold greater potential for human triggering. Locations where this is most prominent include strong lee areas in Tuckerman such as under the Headwall ice, the lower Lip, and the Sluice. In Huntington you’ll find examples in areas such as the start zones of Escape Hatch and South Gully, and under rock buttresses at the tops of the approaches. Good route finding is important but may prove challenging today as clouds lower and new snow helps to obscure your vision.

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 8:30a.m., Friday, February 11, 2011

All forecast areas of Tuckerman have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions exist on specific terrain features.  Evaluate snow and terrain carefully to identify areas of concern.

Huntington Ravine has Moderate and Low avalanche danger. South Gully and the Escape Hatch have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas of Huntington have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow on isolated terrain features.

After a rather active start to the month, we’ve entered a bit of a lull lately. Almost 25″ (63cm) of snow fell on the Summit in the first 8 days. Over the last couple days nothing has been recorded on the Summit and only a couple of traces have fallen lower on the mountain. However, the infamous Mt. Washington winds have done their part to keep the avalanche conditions interesting. Tuesday night winds hit their peak with a gust from the W clocking in at 104mph (168kph). Since then they’ve stayed strong and have been able to sporadically inspire bursts of windloading, such as the banner that could be seen flying over Hillman’s Highway yesterday while winds were sustained in the 50-60mph range (80-97kph). Today the winds are expected to dip below where they’ve been for the past couple days, which will further reduce any active windloading. Conditions will remain fairly static as the cold weather helps to keep things where they’re at for the time being. I would expect to find a mixture of slab hardnesses out there, with everything from steel slab leftover from the 100mph winds to the relatively softer 1-finger slabs in more protected lee areas. Winds over the past few days have been predominantly from the W through the NW, so direct E and SE aspects would be the most in the lee. Examples include under the ice in the Center Bowl, in the Lip and Sluice, and the climber’s right side of Hillman’s Highway. Keep in mind that our snowfields have been maturing quickly in the past couple weeks and they are becoming increasingly connected to one another.

Huntington Ravine took more of a beating from the winds than did Tuckerman. The areas of most concern are in the start zones of the Escape Hatch and South Gully. The snow in these areas were protected more from the full force of the winds, allowing them to develop softer, more evenly distributed slabs. Elsewhere in the Low rated areas, you’ll want to watch out for unstable snow in the wind-protected areas below the rock buttresses on the approaches to the climbs and in areas like the midsection of Yale Gully.

Look for a Weekend Update coming later this afternoon or early evening. We’ll give our thoughts for next couple days including what’s in store for snow later this weekend (but don’t get too excited for that part).

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., Thursday, February 10, 2011

Tuckerman and Huntington Ravines have MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions exist on specific terrain features.  Evaluate snow and terrain carefully to identify areas of concern.

As of early Thursday we continue to have no visibility with light snow falling on the mountain.  About 30 hours ago, just after midnight yesterday morning, we had a temperature of -22F (-30C) and a peak wind of 104mph (168kph).  This set up a scouring scenario in most locations punishing existing slabs and moving the 3.8” (10cm) of new snow and additional snow from above treeline down low in the majority of our terrain.  Drifting exists on the Tuckerman Ravine trail from Pinkham all the way to Hermit Lake.  As yesterday ticked by winds subsided down to 36mph (57kph) by early afternoon, all the while blowing new snow on to the recently scoured surfaces allowing some new slab to be created.  Blowing snow came to a halt overnight even though winds had picked back up to around 80mph for a short period.  The outcome today is a fair degree of spatial variability which will make it difficult to make good travel decisions due to fog and light snow limiting visibility to about 200 feet.  Even though you may be on scoured surfaces where you are, you may not be on stable surfaces just ahead.  Being familiar with the terrain and being mindful of which terrain gets loaded by west winds will be very helpful as I believe these strong lee deposition zones are where you will likely find unstable slabs.  This is particularly true in Tuckerman’s strong lee forecast areas such as high in the Chute, under the headwall ice in the Center Bowl, and in the Lip and Sluice.  Some of these locales may be on the upper end of the Moderate forecast rating.  Expect some cross loading to have occurred in Right Gully and the Lobster Claw especially on the climber’s left side.  Over in Huntington than in Tuckerman you should find more scouring due to the specifics of the terrain and the vortex effect of its narrow gullies. Any unstable slabs in the Huntington gullies are likely to be new since the 100+mph (160+kph) winds referred to earlier. 

With the recent high winds and cold temperatures I would expect any hard slabs that exist to possess good elastic energy which would propagate a fracture easily if failure of the slab is initiated.  This “snapping” release of energy would be most plausible in slab hardness between “pencil” and “1 finger” on the hardness scale.  Thick hard slabs created by 100+ winds that are approaching “knife” hardness we dub “Steel Slab” and often bridge over weaknesses below and support a climber’s weight due to high tensile strength.  These are often very difficult to get a boot edge into and require crampons for a travel as a reference point for you on the hardness scale. Generally speaking, you’ll find the best strength on the hardest, thickest slabs you can find, but you need to use more than general rules of thumb to navigate safely!

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 7:45a.m., Wednesday, February 09, 2011

Tuckerman Ravine has Considerable avalanche danger today.  Natural avalanches are possible and human triggered avalanches are likely.  The Lower Snowfields have Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible. The Little Headwall has Low avalanche danger.  Natural and human triggered avalanches are unlikely in this forecast area. 

Huntington Ravines has Moderate avalanche danger today.  Natural avalanches are unlikely and human-triggered avalanches are possible.

Howling winds are pummeling the mountain this morning as they have been since early last night.  Snow fell through most of the daylight hours yesterday but winds ramped up to 90+mph (145+kph) by midnight and trying to ascertain a snowfall total is near impossible.  From what we saw firsthand I would guess that we picked up 3-4 inches of medium density snow.  In addition to what fell in the last 24 hours the winds have also been able to tear into the older snow.  The crust formed by last weekend’s mixed precip event helped shield some of the snow from Monday’s winds which were strong but not as strong as they are right now.   As speeds pushed higher than they have in the last week, snow that was once protected was torn up and redeposited far from home.  With this in mind the wind transport and loading that continues to occur is probably similar to a 6-8” (15-20cm) storm.  Visibility is nonexistent right now so it’s impossible to say exactly where all of this snow ended up.  I can guarantee that much of it was moved down into the woods where trees provide good wind protection.  Other sheltered locations that likely held onto snow are any protected areas with E to SE aspects. With this in mind the area of most concern in Tuckerman today is the Chute through the Sluice.  In Huntington it would be O’Dell through Yale.  Historically, similar wind speeds have scoured most areas in Huntington and pummeled the snow in the top of Tuckerman’s Left Gully. This may very well be the case today but with no visibility we can’t know for sure.  Each day and weather event is unique and we’re often amazed how different the ravines can react to similar conditions.  Saturday’s mixed precip event not only created a crust in most areas of the mountain but it also dumped a wide variety of precip forms including cold snow, graupel, and ice pellets that were the size of small peas.  Each of these forms reacts differently to winds and contact with other layers.  As a result the spatial variability was high immediately after the storm and these recent winds and any resulting avalanche activity has increased the variety of conditions found in our forecast areas.  If you choose to travel in avalanche terrain today you’ll need to pay close attention to changes in stability as you move over short distances.   

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