Avalanche Advisory for Tuesday, 12-31-2013

Expires at 12:00 midnight Tuesday, December 31, 2013.

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Lip, Center Bowl, and Hillman’s Highway have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Lobster Claw, Right Gully, Chute, Left Gully, Lower Snowfields, and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow in isolated terrain features within these locations.

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully, Pinnacle, and Odell have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely. Watch for unstable snow in isolated terrain features within these locations.

AVALANCHE PROBLEM: Windslabs leftover from yesterday’s howling winds are the problem of the day. Many of our forecast areas were hit hard by the winds and had their snow removed either by avalanche activity or by scouring action. These are currently rated Low and offer the best opportunity to avoid unstable snow in steep terrain. However, in these areas you should be on the lookout for smaller pockets that may harbor unstable snow. The areas rated Moderate were the most protected against the strong W winds and have greater potential for someone to trigger an avalanche.

WEATHER: It’s a calm, clear, and cold morning today, but this may only be a brief window of good weather before clouds lower and engulf the mountain by late day. Winds will be on the increase, rising to 40-55mph (64-89kph) by dark. Additional snowfall up to 2” may come, but should hold off until late in the day. New snow falling with expected wind speeds will start to form new windslabs; this may become a problem if you are out on the mountain after dark.

SNOWPACK: Despite getting a 12” storm just two days ago and a total of 66” for the month at the Summit, overall snow coverage in both ravines is still pretty thin. This is due in large part to a lack of snow in October and November, and also to the thaw from about a week ago. Yesterday’s 103mph peak gusts removing snow from Huntington can also be a factor in the overall thin cover. Our snowpack is still very discontinuous, even in some of the most protected terrain such as the Center Bowl. As usual, there is a lot of variability as you move around. The crust that formed a week ago is currently the most likely bed surface for any avalanche activity. Above this you’ll find a variety of conditions, including some areas that are strong and some that are weak.

 

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.
  • Posted 8:30 Tuesday. Tuesday, December 31, 2013.  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

2013-12-31 print friendly

Avalanche Advisory for Monday 12-30-2013

This advisory expires at 12:00 midnight, Monday December 30, 2013

The Lion Head Summer Trail is now closed. Please use the Lion Head Winter Route.

Tuckerman and Huntington Ravines have HIGH avalanche danger today. Very dangerous avalanche conditions exist. Travel in avalanche terrain is not recommended. Natural avalanches are likely and human triggered avalanches are very likely. Exceptions to this rating include Lobster Claw, Right Gully, and the Lower Snowfields in Tuckerman which have CONSIDERABLE avalanche danger. Natural avalanches are possible and human triggered avalanches are likely in these areas. The Little Headwall has Moderate avalanche danger. Human triggered avalanches are possible.

AVALANCHE PROBLEM: As mentioned, TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED. This includes walking up into the low angled terrain at the base of either ravine. You do not need to be on a steep slope to be within striking distance of naturally triggered avalanches today. I expect there will be multiple avalanches in many of our forecast areas. The primary problem is storm slabs that began to build last night and will continue to develop as winds are able redistribute significant amounts of snow today.

WEATHER: The recent storm is one to make us smile. Storm totals as of this morning were 13.2” (33cm) at the summit, 12” (31cm) at Hermit Lake, and 11” (28cm) at Harvard Cabin. Densities are consistent at about 8-9% at each location. At the onset of snowfall, winds were fairly light, coming from the E in the 15-25mph range. With heavy snow falling overnight, winds swung counter-clockwise and steadily increased velocity. At 7a.m. today they are blowing from the W in the 60-80mph range. The speeds are expected to remain strong, although the direction will shift back a bit towards the NW. Temperatures will be falling through the next 12 hours to below zero F. Expect a significant amount of windblown snow if you go above treeline today.

SNOWPACK: About one week ago the mountain fell back below freezing after a prolonged December thaw. This created an icy crust that was a dominant surface condition in many locations this past week. A few inches of light density snow had fallen during the week and were loaded into windslabs located in the strongly sheltered locations in the ravines. One of these slabs, in the Lip area, proved itself unstable on Saturday evening as a party of two hikers triggered an avalanche that carried them to the floor of Tuckerman.

These two surface conditions, the icy crust and the sensitive windslabs, are what the new snow has fallen onto. With the winds slowly ramping up during the storm, we likely had some avalanche activity overnight as denser slabs were able to build on top of relatively weaker snow that had not been wind-effected. If a path has not yet slid, it will have this very weak layer waiting for sufficient load to release it. If it has already slid, then we can expect continued reloading of new slab onto an existing bed surface. All this equates to a strong likelihood of avalanche activity in most areas today.

The areas not posted at High danger have only begun to fill in with snow for the season, so they have smaller potential bed surfaces. Recreational opportunities are limited in these areas (i.e. the bushwacking is miserable) but you should remember that Considerable is still a dangerous rating in which to be out recreating.

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.
  • Posted 8:00a.m. Monday, December 30, 2013. 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

2013-12-30 print friendly

Avalanche Advisory for Sunday 12-29-2013

This advisory expires today at midnight.

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Moderate avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible. Lobster Claw, Right Gully, Lower Snowfields and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.  These Low areas are mostly a bushy rocky landscape lacking any sizable slopes for unstable slabs or traveling.

Huntington Ravine has MODERATE avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

AVALANCHE PROBLEM:  Today we continue to have a combined avalanche problem of left over Storm Slabs and Wind Slabs.  Although many bed surfaces in our terrain are still broken up by rock cliffs, turf, and ice bulges limiting their size they are large enough to harbor unstable slabs sensitive to a human trigger.  This was tested last night when 2 hikers came down from summiting Washington and traveled into “the Lip” at dark and triggered an avalanche carrying them down to the floor of the Tuckerman Ravine.  They miraculously survived but sustained injuries requiring rescue during the overnight.  Through history there have been a number of very lucky people in the world, they are now 2 more of them.  More information will be posted in our accidents page later today.  Variability in our snowpack stability is still substantial.  In many areas you will find old hard surfaces such as down low in Left Gully, Central Gully and Odell while in many others such as the Sluice, Center Bowl and the Chute you will find unstable wind slabs with poor to fair strength.  If you transition from stable old surfaces to new slab of varying depth, I would be very skeptical about their strength.  A potential initial failure in their weaker thin areas may rip into deeper sections.  These problems will be complicated by the Winter Storm moving into the mountains this afternoon.

WEATHER: Winds will shift to the SW and decrease to 25-35+mph today in prelude to a WINTER STORM moving into the region later this afternoon.  The current NWS issued WARNING begins at 4pm this afternoon.   We expect 4-8″ of new snow before it wraps up Monday morning. Winds will shift briefly to the S before returning to the W and raging during the early morning hours approaching 100mph (160kph).  Expect new loading on a variety of aspects based on the shifting wind.

SNOWPACK: There are a number of locations such as Central and Pinnacle in Huntington that may take all day to reach their forecasted rating.  This is due to generally stable old surface conditions that exist this morning.  They are starting the day at Low although isolated pockets of instability exist.  This will change late in the day due to the incoming afternoon snow.  Other areas particularly E facing slopes in Tuckerman have a solid Moderate rating this morning and will be bumping the ceiling of their definition, hedging towards Considerable late in the day.  This likely won’t happen till after dark, but it is all something to keep in mind in your decision making today.

Icy conditions still exist. Crampons and an ice axe are required for safe travel in steep terrain and other traction footwear for travel on low elevation hiking trails.  Generally speaking microspikes are for lowland trail travel and not suitable for mountaineering terrain and alpine zone conditions.  Sherburne ski trail coverage is very thin with last night’s rescue snowcat tracks.  Although a bit bumpy the grinding of the icy surfaces helped it and will hold the storm snow much better than yesterdays’ ice. Long sliding falls are possible. Realize that in locations scoured by high winds such as Left or Central Gully, and in locations where snow is thin, the icy surface with be hard to self-arrest on making it very difficult to stop yourself if you fall.

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. Posted 0855. 12-29-2013. 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

2013-12-29 print friendly

Avalanche Accident in Tuckerman Ravine

Two hikers descending from the summit triggered an avalanche that carried them down the Lip of Tuckerman Ravine.  In this incident, a group of four hikers started up from Pinkham Notch Visitor Center. Along the ascent, the group separated into two teams of two. Descending in poor visibility and fading daylight, the faster team lost the trail and inadvertently began descending the Lip. This forecast area had been rated Considerable avalanche danger due to expected wind loading late in the day. The slower team, realizing the other party had gone off trail, followed their tracks to the crown line of the avalanche. From there they were able to verbally communicate with their friends and learn the extent of the injuries. They decided it would be safer to descend the Lion Head Summer Trail to summon assistance.

As an avalanche forecasting center, we were not surprised that the party triggered an avalanche in the location they did. Considerable danger includes “human triggered avalanches are likely” in its definition. Weather conditions in the days prior to the accident created conditions ripe for avalanche activity. About a week before the accident, Mt. Washington was subjected to a warm rain event. This created slick crusty snow surface conditions for future snow and wind-loading land on and create new stability problems. In the 48 hours prior to the event, about 10.5” of new snow had fallen, with 1-3” having been forecasted for the 28th. During this time, west and northwest winds also increased in speed from 30-40mph to 60-80mph. This created a situation with increasingly dense slab building on top of weaker layers, all of which sat on the pre-existing crust.  This is a typical scenario for Mt. Washington; one in which we regularly see human triggered or naturally triggered avalanches.

The hikers rode the avalanche to the base of the Open Book, adjacent to Lunch Rocks. Along the way they sustained non-lifethreatening injuries. In the debris, they ended up only partially buried or on top of the snow, one was at the toe of the debris and the other at the top of the debris. They reported taking about a half hour to collect themselves and figure out what happened. They also did not understand where exactly they were, or that the Tuckerman Ravine Trail could be followed downhill from their location. They knew they had fallen a long way below the trail they intended to descend, so they began to climb back up, which is when they began communicating with their friends above.

The uninjured hikers arrived at the AMC Caretaker’s quarters to tell her of the accident. She quickly notified USFS Snow Rangers, who began mobilizing rescue teams. Rescuers included USFS Snow Rangers, members of Mountain Rescue Service and Androscoggin Valley Search and Rescue, caretakers from the AMC and HMC cabin, and a handful of helpful bystanders who were staying overnight at the Harvard Cabin. The rescue itself was not particularly noteworthy. A rescue team climbed to the injured hikers, assessed and treated their injuries, and short-roped them down to the floor of Tuckerman. From there the hikers walked down under their own power to Hermit Lake to a waiting snow tractor. They were then transferred to an ambulance at the bottom of the Sherburne Ski Trail.

Analysis:

This is an accident that could have been avoided if just a couple small factors played out differently. Most obviously, if the group had stayed together and stayed on the Lion Head Trail, they would never have entered avalanche terrain.  The two more experienced hikers had been planning to do an overnight at Hermit Lake, while the two with less experience were only doing a day trip. Hence, the two with lightweight daypacks were able to move more quickly than the heavily-laden duo. This was the primary reason for one group going faster than the other, as we understand. The plan had been for the hikers to all regroup at the summit, but the faster group went down ahead. Often in incidents involving missing or overdue hikers, splitting the group is a contributing factor. Many times there is no contingency plan made, or if there is one it is not followed. In this event we don’t know exactly what their meeting plan was. However, if they had either kept the group together for the duration, or stuck with the plan to regroup,  the chances for staying on the trail and avoiding the incident would have been better.

Avalanche Advisory for Saturday December 28th, 2013

This advisory expires today at midnight.

Tuckerman Ravine has CONSIDERABLE and LOW avalanche danger.   The Sluice, Lip, Center Bowl, Chute, Left Gully, and Hillman’s Highway have Considerable avalanche danger today. Natural avalanches are possible and human triggered avalanches are likely. Lobster Claw, Right Gully, Lower Snowfields and Little Headwall have Low avalanche danger. Natural and human triggered avalanches are unlikely.  These Low areas are mostly a bushy rocky landscape lacking any sizable slopes for unstable slabs or traveling.

Huntington Ravine has CONSIDERABLE and MODERATE avalanche danger.  Central, Pinnacle, Odell, South and Escape Hatch have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. North, Damnation and Yale have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

AVALANCHE PROBLEM:  Today we continue to have a combined avalanche problem of Storm Slabs and Wind Slabs.  An additional 2” (5cm) last night brings the recorded summit total to 10.5” (26cm) over the past 48 hours.  Through Saturday another 1-3” (2.5-7.5cm) of snow is forecasted which will be adding to our stability issues today.  As temperatures climb new snow density will rise contributing to denser slab development over the lighter layers from yesterday.  Moderate to high winds have loaded in snow from above treeline mixing with snow falling from the sky. This developed slabs predominately in our strong lee areas that have an E facing component due to mostly a W wind.  This main concern is followed by aspects facing NE and SE.  It will be important to constantly assess stability as you move because you will find a lot of variability.  This runs the spectrum from scoured hard surfaces generally down low and in the open, to new slabs generally in higher regions in Tuckerman and often lower in the Huntington approaches.

WEATHER: Light upslope snow continued on and off through the night delivering an additional 2” (5cm) totaling 10.5” of 6.2% density over the past 48 hours.  W winds from 50-70mph yesterday have ticked up this morning and are expected to move into the 80’s over the next few hours before subsiding later.  An additional 1-3” of snow is expected today which will mix in with drifting snow from alpine zones creating more unstable snow.  A Winter Storm Watch is in effect for Late tomorrow into Monday morning.

SNOWPACK: This upslope event with cold air in place and a wind that has gone up and down over the past 2 days has given us a number of new concerns.  Slick bed surfaces before the snow onset on Thursday were loaded with a moderate wrapping wind starting us out with low density slabs on an icy layer.  Moderate to high winds since continue to load a number of strong lee areas with thicker slabs.  Although we are still socked in with clouds and blowing snow we believe you will find quite spatially variable conditions as you move around.  A number of areas are likely scoured down to old surfaces due to high winds, icy old bed surfaces, and low density snow.  You will also find unstable new Storm and Wind Slabs in protected terrain.  In some locations it may include the majority of the forecast area such as in the Center Tuckerman Bowl. In others it may only be in one location, but that may be enough such as the approach to Pinnacle’s first pitch in Huntington.  The only consistent factor is the nature of any slab failure today.  You will find shear failure within new snow likely in lower density slab that was deposited during periods of lower wind speeds.  Depth of this failure is going to be quite variable depending on location.  In our bottom line forecasters discussion this morning we felt we are closer to natural avalanches be possible than unlikely due to increasing wind speeds and up to another 3” (7.5cm) of snow today.

Icy conditions still exist. Crampons and an ice axe are required for safe travel in steep terrain and other traction footwear for travel on low elevation hiking trails.  New snow will hide slick sections as well as rocks and holes between rocks.  Recent new light density snow will amount to less than 6″ from Hermit Lake down the Sherburne and will hide rocks, water ice and death cookies of refrozen crust. Sherburne ski trail coverage is very thin. Long sliding falls are possible. Realize that in locations scoured by high winds, and in locations where snow is thin, the icy surface with be hard to self-arrest on making it very difficult to stop yourself if you fall.

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. Posted 0828. 12-28-2013. 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

2013-12-28 Print

Avalanche Advisory for December 27, 2013

This advisory expires today at midnight.

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

Huntington Ravine has Considerable and Moderate avalanche danger.  Central, Pinnacle, Odell, South and Escape Hatch have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. Dangerous avalanches conditions exist. North, Damnation and Yale  have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

AVALANCHE PROBLEM:  Storm snow yesterday and today will be part of our problem today along with wind slab developing later in the day as wind speeds increase. 7+” of light density snow fell in the higher terrain yesterday which has formed touchy and reactive storm slabs. This snow will be overlaid with denser  wind slab today creating a dangerous mix of reactive slabs, which will gain thickness, mass and potential energy as the day continues, to negotiate. Poor bonding surfaces in the form of cold ice and rock features as well as a relatively thin snowpack over rocky, bushy terrain are all widespread issues in both ravines. Thinly covered rocks and unburied terrain traps increase the hazard of any sliding fall or avalanche. These problems are likely to continue through the weekend.

WEATHER:  Snowfall yesterday exceeded expectations ending with almost double forecasted amounts.  Consistent rates of s1 to s2 produced 6.6” (17cm) on the summit as of midnight.  Light snow has continued since then and is expected through the day.  Overall, by the time the upslope precipitation ends, we should have a total event accumulation between 8.5” (21.5cm) and 10.5” (26.5cm).  Snow density has been between 6-7% and we expect this trend to continue with the low temperatures firmly in place.  At the onset of Thursday’s precipitation, winds were from the S and SW where they remained before transitioning to the West late in the afternoon.  Generally, wind velocity remained between 35mph (56kph) and 50mph (80kph) before picking up after dark.  Winds from the W are expected to gain strength today gusting over 70mph (112kph) this afternoon and building towards 90mph during the overnight and into Saturday morning.  This will continue loading new snow today and tonight.

SNOWPACK: Yesterday’s snowfall began cold and dry, likely bonding poorly to the icy surfaces left behind by the recent ice storm and rain.  It is plausible that we endured a number of smaller natural avalanches and dry loose sluffs late in the day due to the moderate winds, low density snow, and slick bed surfaces.  Winds shifted from the SSW late in the day and have loaded predominately E facing slopes overnight which will continue through today.  The wind history over the past 24 hours has therefore loaded the start zones from N facing through E and SE aspects.  It is likely that building winds will break apart crystals at an increasing rate and pack them into denser slabs over yesterday’s low density slabs creating an unstable scenario.  We would anticipate unstable slabs on the majority of the existing snowfields, however small, in both ravines.  Due to the wide distribution of instabilities of Storm Slabs and Wind Slabs even the skilled and experienced user will find it difficult to avoid potential natural avalanches or being a trigger due to the touchy nature of the cold low density snow.  Stability test results may be variable, but should give you a consistent message-poor stability.

In addition to avalanche problems the following hazards should be factored into your travel plan.

Generally icy trail conditions still exist. We highly recommend crampons and an ice axe for travel in steep terrain and other traction footwear for travel on low elevation hiking trails.  New snow will hide slick sections as well as rocks and holes between rocks.  Recent new light density snow will amount to less than 6″ from Hermit Lake down the Sherburne and will  hide rocks, water ice and death cookies of refrozen crust. Sherburne ski trail coverage is very thin.

Long sliding falls. In those locations where continuous snow coverage exists, the icy surface beneath light density snow will make it difficult for you to stop yourself if you fall. The thin layer of new, low density snow will make assessing the traction of each step challenging.

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. Posted 0823 a.m. 12-27-2013. A new advisory will be issued tomorrow.

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

2013-12-27 Print friendly

Avalanche Advisory for Thursday December 26th, 2013

This advisory expires today at midnight.

Tuckerman and Huntington Ravines will have MODERATE avalanche danger today. Natural avalanches are unlikely and human triggered avalanches are possible.   This pertains to all forecast areas except Tuckerman’s Lobster Claw, Right Gully, Lower Snowfields and Little Headwall as well as Huntington’s North, Damnation and Yale which all have Low avalanche danger.  Natural and and human triggered avalanches are unlikely except in isolated terrain features.  Depending on accumulations expect an increasing avalanche danger with all areas hedging to the next rating level if forecasted snow fall depths occur earlier than expected.

AVALANCHE PROBLEM:  The existing snowpack at sunrise today is quite stable so we will start the day with very little avalanche concern, but as the day wears on this will change.  Later today Storm Slabs will be something to look out for due to new snow today and tonight.  A Storm slab problem is the concern for a relatively soft cohesive layer of new snow that fractures and fails within the storm snow or on the old snow surface.  This old snow interface is currently slick and hard from the recent ice storm and should make a good sliding surface and conducive to easy shear failure.  We would expect new cold snow to bond poorly to this current surface.  Also expect a Loose Dry Snow avalanche problem in our steepest terrain.  This sluffing of unconsolidated snow is conducive with cold dry snow and slick steep surfaces.  Expect this on climbing routes and other steep or stepped terrain.  Sluffs could build into new cohesive slabs of concern if re-distributed within avalanche terrain causing a secondary problem.  This is a common problem in the Huntington Gullies, particularly Pinnacle, Odell and Central.

WEATHER: Today 2-4” of snow is anticipated with an additional 1-3” tonight.  Winds are currently from the SW at 225 degrees on the compass rose, but are forecasted to shift to the W and gust into the 70’s late in the day.  Winds should subside during the overnight before ramping back up over 80mph tomorrow giving us another loading event from additional snow.  New snow density should be light and fluffy due to temperatures in the 5-10F range.

SNOWPACK: Our snowpack took it on the chin during the severe rain beating ending a few days ago.  Due to this snowpack reboot, this morning you will find a fairly uniform and well bonded snowpack.  I would anticipate the new snow today to bond poorly to the existing surface.  Low density snow crystals will survive a bit better this morning with lower wind speeds than they should this afternoon. Therefore, the initial layer should be a bit softer than slabs developing late in the day.  As winds shift and increase I expect crystal fragments to pack into denser slabs later.  If this scenario plays out a dense cohesive slab may form over a weaker one sitting on an old slick bed surface.  With this said 2-4” today and 1-3” tonight is hardly a major storm, but with building winds from the W and poor to fair bonding expected, new slabs should be respected. Depending on actual totals you shouldn’t be surprised to see increasing instability and increasing avalanche danger.  Also expect tremendous spatial variability as much our terrain is broken up by terrain features and brush.  This will create many isolated problems, often resulting in small avalanches. At a minimum these small avalanches have enough force to knock you down and carry you through the terrain. This is generally true for the majority of both Ravines although larger bed surfaces do exist in The Chute, Left Gully, and Huntington’s Central gully.

In addition to avalanche problems the following hazards should be strongly kept in mind.

Generally icy trail conditions and breakable crust if you venture off the beaten path. We highly recommend crampons and an ice axe for travel in steep terrain or other traction footwear for travel on low elevation hiking trails.  A thin layer of new snow will hide slick sections increasing this icy hazard.  Expect the Sherburne ski trail to be particularly awful if new snow hides water ice, death cookies and frozen turkeys.  I would avoid it as every lump of frozen snow might as well be granite.

Long sliding falls. In those locations where continuous snow coverage exists, the icy surface will make it difficult for you to stop yourself if you were to fall. A thin layer of new low density snow may decrease your friction co-efficient allowing you to break the sound barrier a bit quicker than normal.  Self-arrest must be instantaneous or expect Mach 1 (1126ft/s or 340m/s)  to Mach 1.3 (1464ft/s or 442m/2) speeds followed by the boom of the sound barrier.  Every movement should be done with a deliberate caution.

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. Posted 730a.m. 12-26-2013. 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

2013-12-26 Print

Avalanche Advisory for Wednesday, 12-25-2013

Expires at 12:00 midnight Wednesday, December 25, 2013.

All forecast areas of Tuckerman and Huntington Ravines have Low avalanche danger today. Natural and human triggered avalanches are unlikely except in isolated terrain features.

AVALANCHE PROBLEM:  The existing snowpack is quite stable; very few avalanche problems currently exist on Mt. Washington. Other mountain hazards will play a far more prominent role in your travels. These include:

  • Generally icy trail conditions and breakable crust if you go off the beaten path. We highly recommend crampons and an ice axe for travel in steep terrain or other traction footwear for travel on hiking trails. Remember that the trails that pass through Tuckerman and Huntington ravines are buried under snow and ice, which makes them more of a mountaineering adventure than a casual hike.
  • Long sliding falls. In those locations where continuous snow coverage exists, the icy surface will make it difficult for you to stop yourself if you were to fall.
  • Ice dam formation. This is something that climbers in Huntington need to know about. As temperatures drop, drainage channels get plugged with ice, causing water pressure to build behind the ice. This can be annoying or it can be very dangerous, but you never know which until you release the pressure with your ice tool or crampon.

WEATHER: As mentioned, we had a long thaw and rain event last weekend. On Monday, temperatures fell back below the freezing point. So the mountain has now been below freezing for a couple days. On Monday night, we received 1.6″ of snow at the summit, but only found 1cm of snow at our study plots lower on the mountain. Today should be a pleasant day by Mt. Washington standards. There is some snow in the forecast for Thursday. At this time, 2-4″ are forecast.

SNOWPACK: Our snowpack took a beating from the rain. If you are looking for an interesting, layered snowpack, you’re unlikely to find it here. What you will find is a uniform layer of refrozen grains of snow, capped off with a freezing rain crust and a dusting of new snow. In some isolated terrain features, you may find deeper pockets of new windslab on top of this crust. After what I saw in the field yesterday, I don’t think many of these will be deep enough to be a problem, but if you should find a deeper one, there is a good chance it will be sensitive to triggering.

Current snow coverage is thin across the mountain. If you were to ask, I wouldn’t recommend coming up here just to ski the Sherburne. In fact, if you were already at Pinkham with skis on your pack, I’d actually try to dissuade you from bringing them up.

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.
  • Posted 6:40 Wednesday, December 25, 2013.  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

2013-12-25 print friendly

Avalanche Advisory for Tuesday, 12-24-2013

Expires at 12:00 midnight Tuesday, December 24, 2013.

All forecast areas of Tuckerman and Huntington Ravines have Low avalanche danger today. Natural and human triggered avalanches are unlikely except in isolated terrain features.

AVALANCHE PROBLEM: Be aware of the potential for isolated pockets of windslab today. Last night the summit received 1.6” of new snow along with WNW winds; this is often just enough snow and wind to create problems in areas sheltered from the winds, such as the Lip of Tuckerman or parts of Central Gully in Huntington. There is really not much to say for widespread avalanche problems today. After a prolonged thaw with ample rain, temperatures have plummeted and the older snowpack has locked up in ice.

Outside of avalanche problems, there are other hazards you ought to be thinking about. The first is generally nasty hiking conditions, especially if you go off the beaten path. We highly recommend crampons for travel in steep icy terrain or other traction for travel on hiking trails. Another problem you may encounter is ice dam formation. As temperatures drop, drainage channels get plugged with ice, causing water pressure to build behind the ice. This can be annoying or it can be very dangerous, but you never know which until you release the pressure with your ice tool or crampon.

WEATHER: Today’s increasing winds may allow some additional snow loading, but this should not be significantly contributing to the further development of avalanche potential. You should take a moment to review the weather forecast before heading above treeline today. Temperatures will be falling to subzero F while winds ramp up through the day, going past the hurricane force criteria this evening. Add lowering cloud levels to the mix and this all makes today a good day to move efficiently and get off the mountain early.

Looking into the future, Christmas Day looks to be a more pleasant one on the mountain. This will be followed by a chance for a light snowfall on Thursday and then more high pressure for the weekend. Unfortunately, we have no significant snowstorms looming on the immediate horizon.

SNOWPACK: Our snowpack took a beating from the rain. If you are looking for an interesting, layered snowpack, you’re unlikely to find it here. What you will find is a uniform layer of refrozen grains of snow, capped off with a freezing rain crust and a dusting of new snow. In some isolated terrain features, you may find deeper pockets of new windslab on top of this crust. These areas should be approached with caution.

Current snow coverage is thin across the mountain. If you were to ask, I wouldn’t recommend coming up here just to ski the Sherburne. As for heading into the ravines seeking snow, don’t expect much there, either. The gullies of Huntington have more exposed rock than is typical for this time of year.  The same goes for Tuckerman; it’s pretty bony up there. That said, the summer hiking trails through the ravines are buried under snow and ice, making them full blown mountaineering adventures rather than just a challenging hike. With any luck today, I’ll get some breaks in the clouds and be able to get some photos posted online.

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.
  • Posted 7:30 Tuesday. Tuesday, December 24, 2013.  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

2013-12-24 print friendly

Avalanche Advisory for Monday, 12-23-2013

Expires at 12:00 midnight Monday 12/23/2013

All forecast areas of Tuckerman and Huntington Ravines have Low avalanche danger today. Natural and human triggered avalanches are unlikely except in isolated terrain features.

AVALANCHE PROBLEM: The lump of coal that Santa delivered us in advance of Christmas came in the form of a late December thaw event. The peak period of instability related to the warmth and rain is now behind us, leaving behind a snowpack that will be in the process of locking up in ice later today. While you wait patiently for temperatures to fall, you should be thinking about the chances for lingering wet slabs to release. The chances are unlikely that any unstable slabs still exist, but remember that unlikely does not mean that same as impossible. The consequences of a slip, trip, or fall in current conditions can be dire.

Outside of avalanche problems, there are other hazards you ought to be thinking about. The first is generally nasty hiking conditions, especially if you go off the beaten path. We highly recommend crampons for travel in steep icy terrain or other traction for travel on hiking trails. Another problem you may encounter is ice dam formation. As temperatures drop, drainage channels get plugged with ice, causing water pressure to build behind the ice. This can be annoying or it can be very dangerous, but you never know which until you release the pressure with your ice tool or crampon.

Finally, there is a chance for a small amount of snow late today. This may load into small pockets of unstable windslab late in the day. This problem will only form after the changeover from rain to snow, which isn’t forecast to happen until late afternoon.

WEATHER: The summit recorded over an inch of rain in the past 48 hours with the heaviest period of rain falling Saturday afternoon. The cold air damming that resulted regionally in widespread freezing rain played out in the mountains as warmer air aloft that allowed more of the precipitation to fall in liquid form. Fog and freezing fog will reduce visibility throughout the day with rain transitioning to snow as the  low pressure currently in place is pushed out to sea. Liquid equivalents (QPF) of .25” are forecast which will fall as rain, freezing rain then snow as temperatures drop. Expect a wide range of weather conditions today.

SNOWPACK: Our snowpack took a beating from the rain. Summit measurements showed 12” on the ground 48 hours ago reduced to 1” by yesterday afternoon. Snow surface conditions will remain soft for the forecast period until lockup due to falling temperatures through the day and into tomorrow. It is unlikely that you’ll find cold dry snow anywhere except low in the deepest wind-loaded areas. Peak instabilities due to rain on snow have peaked and we are in a stabilizing trend as percolating water delivering heat into our thin, early season snowpack slows.

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.
  • Posted 7:30 Monday 12-23-2013  A new advisory will be issued tomorrow

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

2013-12-23 Print Friendly