Avalanche Advisory for Sunday, January 31, 2016

Tuckerman Ravine has MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions on specific terrain features exist. Evaluate snow and terrain carefully to identify features of concern.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover.

Huntington Ravine has MODERATE and LOW avalanche danger. Central Gully has Moderate avalanche danger.  Natural avalanches are unlikely and human-triggered avalanches are possible. Pinnacle, Odell and South have Low avalanche danger. Natural and human-triggered avalanches are unlikely. North, Damnation, Yale, and the Escape Hatch are not posted due to lack of snow cover. Exercise caution in these areas and expect the potential for isolated patches of instability particularly around pitches of water ice.

AVALANCHE PROBLEM: Wind slabs are the avalanche problem today. Yesterday, the wind shifted to the southwest and west increasing in velocity, and in the process, built new wind slabs in sheltered areas of both Ravines. The underlying softer snow is the weak layer in these surface slabs, however the slab on top is not likely to be particularly touchy or widespread across the terrain. Another factor which helps push our Moderate rating down to the lower end of the definition, is our bedsurfaces which are generally still small.  Even the terrain in our strongest prevailing lee locations such as Odell and Pinnacle in Huntington and the Lip and Center Bowl in Tuckerman are lacking the snowcover needed to harbor large continuous slabs. Still, use caution when moving around in the Ravines today. Steep terrain features with patches of somewhat unstable snow and rocky runouts should still command respect.

WEATHER: Temperatures gradually warmed to the upper teens and 20’sF (-6.5C) in our Ravines yesterday and have continued to rise slowly overnight. WSW winds in the 50 to 60 mph (80-96kph) range late last night loaded some of our forecast areas with more of the available snow from the alpine as well as the 1.3” (3cm) of new snow. This filled ski and boot tracks in Left and Right Gully that were made mid-day yesterday. Expect W winds in the 35-45mph (56-72kph) range with some higher gusts today increasing to 55-65mph (88-104kph) after dark. The temperature will continue to rise to near the freezing point on the summit today. Today’s warming trend is unlikely to adversely affect snow stability.

SNOWPACK: Yesterday’s wind slabs were fairly soft (4F) and non-reactive to the human-triggers that were out and about. The lighter density snow beneath was not significantly lower in density and did not create much of a stability issue. The new loading that happened late yesterday and last night may have made a firmer slab atop all this so evaluate these layers for signs of stability before committing yourself to a larger expanse of snow. There are older wind slabs and deeper faceting beneath associated with the basal ice crust and another melt freeze crust above that is scattered around our terrain. In most areas it is deeply buried or bridging well between anchors. The upcoming warming trend may weaken and destabilize the overlying hard slabs but it remains to be seen how much the upcoming precipitation will load our slopes and how deeply the warming will penetrate. Keep these issues in the back of your mind as we move into the next few days.

The Lion Head Winter Route is open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are helpful on lower elevation trails, but are not substitutes for crampons and an ice axe on this route. The John Sherburne Ski Trail is passable but has become harder with expanding water ice each day. This issue can be added to many waterbars and occasional rocks. Very thin new snow will likely hide some of these demons. Expect very challenging conditions.

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 8:45 a.m. January 31, 2016. A new advisory will be issued tomorrow.

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

2016-01-31

Avalanche Advisory for Saturday, January 30, 2016

Tuckerman and Huntington Ravine have MODERATE avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Heightened avalanche conditions on specific terrain features exist. Evaluate snow and terrain carefully to identify features of concern.  Lobster Claw, Lower Snowfields, and the Little Headwall in Tuckerman and North, Damnation, Yale and the Escape Hatch in Huntington are not posted due to lack of snow cover. Exercise caution in these areas and expect the potential for isolated patches of instability particularly around pitches of water ice.

AVALANCHE PROBLEM: New Wind Slabs are the primary avalanche problem today.  New snow with initial low winds that became much higher has created new soft slabs that should be reactive to human triggers in protected lee slopes.  This is especially a concern high in both Ravines and below steep areas that have sluffed off, like near the base of steep water ice. Additional snow tonight and Sunday night will likely leave Wind Slabs as a threat through the weekend.

WEATHER: By midnight the summit received 3.7″ (9cm) of 8% snow with several more hours of lingering snow showers before shutting down very early this morning.  Winds speeds increased through the evening from the WNW at approximately 50-60mph (80-96kph).  This morning winds are beginning from the WNW, but should shift through the W to the WSW or SW this afternoon and then progress back to the W late, all the while increasing. The mercury, starting in the singles this morning, will climb close to 20F (-6.5C). Overnight winds will exceed hurricane force gusting to 90mph (144kph) on the summit, with another 1-3″ (2.5-7.5cm) of snow expected. Tomorrow winds will diminish, after early high velocities, with temperature rocketing above freezing.

SNOWPACK:  The vast majority of your snow focus should pay attention to the new 4″ (10cm) of snow overnight and the instabilities it likely produced.   This precipitation began yesterday afternoon on very light winds which plausibly created a thin unconsolidated weak layer of light density snow.  As winds picked up with additional snow, soft slabs with an increasing density likely developed, particularly higher in the start zones and lower beneath steep sections.  I would be looking for thin touchy slabs in sheltered locations that are protected from the effects of WNW, W, and WSW winds.  The base of ice pitches is a classic location in both Ravines to find instabilities due to being sheltered from scouring and all the sluffing snow that builds up into thicker slabs.  Due to sluff pounding you will usually find these are denser slabs as well.  Snowfields from the Lip, across the Tuckerman headwall, to Left Gully are some specific locations to harbor new unstable slabs. You will also likely find variable conditions with some exposed locations blown clean to the old surface.  These will likely be very hard so crampons and an ax will be an essential part of your equipment.  Sections of dust on crust may also hide the lurking stiff layer below.

A number of slopes, particularly with an E facing aspect, will be bumping the ceiling of the Moderate rating later today.  As we move into darkness and slabs grow I would have a greater concern for natural avalanches probably crossing over towards a Considerable rating during the overnight.  Although we generally feel the old hard slabs that have been with us for a while are strong to human triggers it is certainly possible that an over running new slab avalanche could step down into this deeper hard slab. Very high winds tonight and additional forecasted snow will increase the avalanche danger into tomorrow morning. Expect hurricane force winds to move a lot of snow from the alpine zone into Tuckerman and Huntington exacerbating the situation.

The Lion Head Winter Route is open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are helpful on lower elevation trails, but are not substitutes for crampons and an ice axe on this route. The John Sherburne Ski Trail is passable but has become harder with expanding water ice each day. This issue can be added to many waterbars and occasional rocks. Very thin new snow will likely hide some of these demons. Expect very challenging conditions.

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 8:18 a.m. January 30, 2016. 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

2016-01-30

January 17, 2016, Human-triggered avalanche incidents

Synopsis: On Sunday, January 17, a wind slab avalanche cycle on the east side of Mount Washington occurred following a period of moderate snowfall and wind. Two human-triggered avalanches occurred, one of which was widely publicized on social media and in the news. A number of factors led to the incidents which are worth looking into in order to shed light on some of the issues around the events. As is the case with many accidents, it is easy to pick out poor decisions in hindsight. In reviewing incidents, it is also rarely productive assigning blame to individuals compared to what lesson can be drawn. This incident presents an opportunity to highlight what appear to be trends in travel practices and decision making on Mt. Washington.

Weather: The snowfall leading up to the avalanche cycle was a typical upslope snow event which often follows more robust synoptic systems passing through our region. As an air mass is forced up and over the windward side of the range, the cooling process turns lingering atmospheric moisture into snow. In the case of the Sunday, January 17 avalanche cycle, the synoptic storm system had deposited 8” on the mountain on the prior Tuesday and Wednesday. A period of unsettled weather followed with 2” falling Thursday and Friday accompanied by periods of high winds and prolonged low visibility. A natural avalanche cycle occurred sometime during this loading event with the areas beneath Center Bowl and Chute later showing debris piles. By the pre-dawn hours on Saturday, as a Nor’easter passed offshore to the east, snow began to fall again during a 4 hour period of light SE and SSE winds. This snowfall became the weak layer when the wind shifted to the west and increased to the 50 mph range. By Sunday morning, sky conditions were clearing with W wind speeds in the 50’s mph lifting snow plumes with the previous days 5.5” snow (.55” SWE) from the alpine elevations. These plumes were visible from the parking lot at Pinkham Notch in the early morning hours. By 10am cold temperatures and blowing snow had begun to give way to clear skies, sunshine, and light wind.

Avalanche activity: By late morning, skiers and climbers began to test the slopes in both Ravines.  Two skiers reported triggering a small slab (R1, D1) near Lunch Rocks beneath the Lip around 11am. One skier was carried about 20’ before arresting his slide. A little later, a guide entered South Gully in Huntington Ravine causing a slab to collapse and settle in place with no avalanche. At 12:50pm, an avalanche from the mid-section of Chute in Tuckerman Ravine caught and carried the two climbers who triggered the slide. Also caught were a solo skier crossing the runout on his way to Left Gully and two from a group of three skiers climbing up the track below the climbers. Of these five people caught and carried, two received minor injuries, with only one transported to a hospital. An avalanche course and a number of students were approximately 15’ from the moving debris on a 40 degree slope which had avalanched earlier in the avalanche cycle.

Chicken Rock Gully: SS-ASu-R1-D1, reported as 10-15cm deep, 15m wide, ran to elevation of the base of Lunch Rocks

A sub-feature in Tuckerman Ravine often referred to as Chicken Rock Gully.

A sub-feature in Tuckerman Ravine often referred to as Chicken Rock Gully. (image: MWAC, taken morning of Jan 17, 2016)

 

Chute: SS-AFu-R2-D1.5, estimated to be 10-50cm x 30m wide crown, 115m track of 400m path

The scene shortly after the avalanche in Chute. (image from Facebook)

The scene shortly after the avalanche in Chute. (image: from Facebook)

 

A view into the Chute after the avalanche. Crown most likely wraps around out of view to the right. (image: nealpinestart.com)

A view into the Chute after the avalanche. Crown most likely wraps around out of view to the right. (image: nealpinestart.com)

Analysis: We have been seeing both positive trends in avalanche terrain travel choices and decision making as well as trends leaving room for improvement. Unfortunately, the trends needing improvement are all too common.

First, for the positives:

  • Everyone involved was geared up appropriately for winter conditions with the right warm clothing, boots, etc. Despite the reputation Mount Washington has for “the world’s worst weather,” the number of travelers who come unprepared for the cold and wind is astounding.
  • Some of the individuals involved were equipped and trained to apply first aid skills to the injured. Similar to the increasing trend in avalanche education we are seeing, there appears to be an increased interest in becoming more self-sufficient in the mountains. While at times Tuckerman and Huntington Ravines seem like frontcountry recreation areas with Snow Rangers and caretakers at both Harvard Cabin and Hermit Lake, it is important to remember that these locales are indeed backcountry settings and help can often be a long way away.
  • Many of the individuals nearby, and one of the skiers who was in the path, were carrying avalanche rescue gear including beacons, probes, and shovels.
  • Several Level 1 avalanche classes were in progress in Tuckerman Ravine. More and more people each year are seeking out professionally-taught avalanche courses which is a very good thing.
  • At least some of the parties read the General Avalanche Bulletin issued on Saturday morning. This type of Bulletin is valid for up to three days, and was both in effect and posted Sunday morning. The Bulletin accurately described recent and upcoming snowfall and wind loading as well as the developed slopes which would become bed surfaces in this avalanche cycle.

Areas for improvement and lessons to take away:

  • Of the five people caught in the avalanche, none were wearing beacons or carrying avalanche rescue gear. Sadly, this is not that unusual in our terrain. The avalanche class was wearing beacons and carrying rescue gear, as was one skier who was able to get out of the path as well as the two skiers who triggered Chicken Rock Gully. Frequently, climbers leave behind avalanche rescue gear to save weight, leaving no quick course of action should burial occur. Hats off to all who recognize the value of carrying avalanche rescue gear to be searchable and have the committed discipline to carrying it. The gear may or may not save your life should you get caught, but it certainly won’t help you if it is in your closet. Situations change, plans change, and mistakes happen—always carry the gear.
  • Given the clustering of users near the Chute, it seems safe to assume that the Social Proof heuristic was at play. Following some discussion, the avalanche class chose to travel in steep terrain beneath a recently loaded slope. They were followed by the party of two climbers and the three skiers. Whether due to the easier travel following in someone else’s boot track, the erroneous assumption that a slope is safe because someone else already traveled on it, or the belief that other travelers know more than you, this behavior is all too common in Tuckerman Ravine. The two climbers then passed the avalanche class and ventured onto the unstable slope.  This bunching in avalanche terrain forces constant re-evaluation of hazard. Additional challenges exist when trying to rebalance risk on a continual basis based on actions of others outside your control.  This issue has been a factor in many avalanche accidents and fatalities locally, as well as around the world.  Mount Washington has very concentrated avalanche terrain and has a high amount of visitation.  We have seen on many occasions a group descend a route while others are unwittingly climbing up in the same avalanche path. This makes safe travel difficult when instabilities exist on a weekend on Mount Washington. Your party’s movements may be under tight control and stay within your chosen level of accepted risk, but only in the absence of other more unpredictable people.   Take the same scenario, with other people as an uncontrollable variable, and you may increase your risk rapidly.  This issue was demonstrated by this incident.  We often see a compounding effect of visitors concentrating together in unstable conditions when they should be considering staying clear of one another by using fracture limiting terrain features and avoiding runout paths.  This is certainly a major challenge for guided parties, courses and organized parties.  Managing objective mountain hazards like icefall, avalanches, crevasses, etc. is hard enough, but adding subjective hazards due to other parties may be untenable. Every leader must balance the group’s level of skill with their agreed upon risk tolerance on a constant basis
  • An associated concern to the above is the challenges of spreading out to reduce overall risk. While spreading out is a good, basic technique for traveling in or below avalanche terrain it may not be as effective as it is often assumed without a quality pre-plan to reduce risk. This pre-plan would review the actual benefits compared to truly going one at time, how you will communicate when spread out if new observations or decisions need to be made, and is this the best route.  A best route option should always be a constant question.  This can be a difficult decision because the safest route is often less convenient. Again, the effectiveness of spreading out as a team of 2 climbers, 3 skiers, or a large avalanche class are complicated when they are all interacting in the same terrain exposed to the hazards.
  • The two climbers overlooked a red flag when they climbed over a recently reloaded crown line and onto a slope that rises from 40 to 45 degrees or more. Moreover, all parties involved in the Chute incident crossed beneath this slope within 4 hours of a period of active loading. While everyone chooses their own level of acceptable risk, it is unclear whether all parties involved sought out the information needed to make an informed decision by reading the posted General Avalanche Bulletin or seeking the right weather data. Hourly precipitation and weather data can be found here and is included among the list of other useful weather related websites on our site. These sites can be incredibly useful tools in the planning stages of your trip or even in the field when cell access is available (don’t forget a pocket charger or spare battery).

Lastly, a short discussion of MWAC’s published products, and any avalanche advisory for that matter, is worthwhile. It is a valuable topic to expand upon specifically. See “Avalanche Products” in our website Blog, ‘The Pit’ this weekend for a more in depth discussion.

  • A General Avalanche Bulletin, which was published the day before these avalanche incidents, is used to convey hazards that are most typically a problem during the early and late season. This document is a one page narrative describing the hazards, but does not assign a danger rating. It is a broad discussion to highlight that instabilities and avalanche potential may currently exist, although not across the entire forecasting area in each Ravine.
  • It is a common occurrence across the United States to see active visitor use in avalanche terrain and have avalanche accidents before a 5-Scale Avalanche Danger Rating Advisory is utilized. These occur under either Informational Bulletins or no products. These isolated instabilities are acceptable and tolerated without postings due to the limited nature of the issues.  Incidents, although unfortunate, are a national actuality based on statistical probabilities and ever increasing backcountry use numbers. This fact clearly focuses to the importance of possessing avalanche knowledge and field skills.  This is an important reality to note when entering any avalanche terrain whether in the Eastern or Western United States.
  • Gaining and maintaining good avalanche assessment skills, training and experience is critical. If you don’t have this knowledge we would highly encourage you to get it through controlled learning environments versus relying solely on posted advisories.  As stated in our Bulletins and Advisories, it is merely one tool to make field decisions. This is not a disclaimer; it addresses the complexity and nature of avalanches and the inevitable spatial variability we often see.  If the Advisory states one thing and our dynamic weather creates another reality with increasing hazard, certainly go with your observations and neck hackles and not the advisory.  Your future well-being makes it essential that avalanche skills match your desire for playing in the mountains.  It will also help you draw as much as possible from the Advisory tool because we’ll be speaking the same language.

If you have any questions or comments feel free to contact us at mwactucks@gmail.com  We’ll do our best to respond in a timely manner.

Avalanche Advisory for Friday, January 29, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin which is issued when instabilities are isolated within forecast areas and are re-issued every three days, or earlier if conditions warrant. These areas have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  Some of these can be found at the base of Central, Pinnacle and scattered through Odell and South gullies. The North, Damnation, and Yale gullies have good ice growing, but hold very little snow. It is critical that you assess snow and avalanche conditions if venturing into Huntington to determine any localized snow instabilities.

AVALANCHE PROBLEM: A couple inches (5cm) of new snow on light to moderate winds through daylight hours may create spindrifts or Dry loose avalanches and small Wind slabs. The forecasted shifting wind in the 20-30 mph (32-48kph) range around mid-day may crossload a lot of areas rather than build large slabs in relatively few areas. Sadly, we still have what amounts to an early season snowpack with generally small snowfields for recreation. The new snow may also feel like a dust on crust scenario with the underlying firm snow being the primary travel surface. Expect a breakable old wind crust over facets when traveling around rocks and bushes and the potential for long sliding falls on steeper slopes. Check back tomorrow morning for updated snowfall totals as they are likely to create new wind slab problems.

WEATHER: Scattered snow showers are forecasted into Sunday morning with a trace to 2″ (5cm) expected each 12 hour period.  This could add up to a handful of inches by the end of the weekend.  Today, showers are anticipated mainly in the afternoon on a shifting and increasing wind moving from the S, through the W, eventually to the NW late.  Velocities will begin rather light, blowing around 15 mph (24kph), and build towards 50mph (80kph) in the alpine zone by late in the day. As of this morning we are just a few degrees away from the expected high of 20F (-6.5 C).  Temperatures will fall overnight and recover slowly tomorrow while winds grow and shift back to the W. Gusts on Saturday night may exceed 80mph (128kph).

SNOWPACK: Our snowpack consists of  very strong, old wind slabs and while some weak layers exists beneath, it will take considerably more loading than we are likely to see today to overload these layers. Firm slabs (P hardness) have dominated the surface in our terrain for many days now. This surface slab varies in thickness but is very strong in the areas where there is enough continuous snow to be appealing for climbing or skiing. The firm snow is just barely bootable, and edge-able, but the extra security of crampons is a good idea when slopes steepen or when climbing above boulders or cliffs. Needless to say, missing a turn in many areas could result in a long ride on a fast surface. The layer of facets that exists between the basal ice crust from our rain on snow event weeks ago and the old wind slabs is worth looking at and keeping in the back of your mind for the future.

The Lion Head Winter Route is open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are helpful on lower elevation trails, but are not substitutes for crampons and an ice axe on this route. The John Sherburne Ski Trail is passable but has become harder with expanding water ice each day. This issue can be added to many waterbars and occasional rocks. Expect very challenging conditions, particularly if a thin veil of new snow hides these landmines over the weekend.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.

Posted 8:00 a.m. January 28, 2016. A new advisory will be issued tomorrow.

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

2016-01-29

Avalanche Advisory of Thursday, January 28, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEMWind slabs are today’s avalanche problem. Yesterday morning’s light snow added new thin slabs in some isolated areas on top of the older wind slabs that were built by high winds 8 days ago. Be wary of these wind slabs, particularly in steeper terrain. Additionally, the old hard wind slabs are not immune to human triggering just because of their apparent hardness. A thin spot in the firm slab and/or a larger expanse of the existing weak layer can allow these slabs to fail. Remember that cold temperatures have continued at our higher elevations with little heat penetrating the snowpack to bring about bombproof stability.

 WEATHER: This morning, there are clear skies, low wind speeds and temperatures in the single digits on the summit. Clouds will thicken and lower in the afternoon, bringing summit fog and increasing SW wind. A weak low pressure system will pass by us and redevelop offshore, send snow showers our way tonight, tomorrow and over the weekend. Although at this point forecast models are calling for only a couple of inches of snow on Friday and again on Saturday at higher elevations, you should anticipate more wind slabs developing as the high wind associated with this activity will move the snow into our avalanche start zones.

SNOWPACK: Firm slabs (P hardness) dominate our terrain. An underlying weak layer in the form of lower density (1F) wind transported snow exists beneath many areas. These weak layers are often far beneath the surface and may not be impacted by the weight of a person in most areas. However, this deeper layer should be on your radar when choosing your route through our terrain. In fact, several weak layers exist in the snow pack currently that create smooth shear planes for slabs to pop out on during stability tests. However, the firm surface slab, as it often does in our little microcosm of regular hurricane force winds, has exceptional bridging power and spans weaknesses in our snowpack allowing for safer travel in many areas of thicker slab. It is a wise traveler who keeps the remote possibility of triggering a hard slab in the part of their brain that makes route finding choices.

Huntington Ravine, while under a General Bulletin, may harbor some wind slab issues such as at the base of Central, Pinnacle and scattered through Odell and South gullies.  Good visuals show that the northern gullies have limited snow coverage so expect to find long stretches of low angle ice.  The Lion Head Winter Route is now open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are good supplemental tools, but are not substitutes for crampons and an ice axe on this route.  The John Sherburne Ski Trail is passable but becomes harder each day as water ice expands and snow is raked off. Expect challenging conditions.

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 8:00 a.m. January 28, 2016. A new advisory will be issued tomorrow.

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

2016-01-28

Avalanche Advisory for Wednesday, January 27, 2016

This advisory expires tonight at 12:00 midnight.

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human-triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: The primary avalanche problem today is windslab. The most concerning situation to watch out for is the development of new wind slab, if accumulating upslope snow materializes. These would be found in strongly sheltered areas first, then growing in more wind exposed areas later. Secondly, pay attention to the firm, hard wind slabs created during high winds almost 7 days ago. We are in a situation with very lean snow coverage in most areas, which creates an inherently variable snowpack. Your most likely interaction with unstable snow of this type will be near the thinner margins of older slabs. Trigger something from one of these weak points is not completely out of the picture, so you should still stay vigilant. One situation to watch for is being able to kick through the firm slab into weak snow beneath.

WEATHER: Another day…another day hoping to see the upper end of the upslope snowfall potential. We expect there to be scattered snow showers in the mountains today, possibly bringing up to 2″ (5cm), but the more likely scenario is that we’ll see only lighter accumulations. Winds will start strong and begin to diminish somewhat through the day. You can expect some blowing snow, but how much will largely depend on how much snow has fallen.

It’s been a slow week for snow accumulations. Very light snowfalls over the past eight days have totaled only 1″ (2.5cm) of snow on the summit. At Hermit Lake you wouldn’t even know that it snowed at all. Our best hope for something in the near future looks to be a clipper system passing by on Friday, but don’t get overly excited about this one.

SNOWPACK: Yesterday’s field work left Helon and I rather unimpressed by the snowpack. One thing that is for sure, there is a lot of variability out there. Some locations on S-facing slopes had a shiny sun crust, others were just firm wind packed snow. Helon dealt with blowing snow creating sluffs and some thin reactive slabs over in the left side of the headwall, but the overall pattern was for a thick hard slab. In Left Gully, he thought he might break his shovel trying to dig into the surface layer and would have preferred digging with a snow saw. You may find areas where faceted snow is forming underneath the hard slab, near a buried crust. This will be something that we’ll need to keep an eye on in the future. But for now, it doesn’t appear to have much effect on current stability.

Huntington Ravine remains under a General Bulletin. It is important to remember that avalanches can occur under a General Bulletin. The biggest potential areas are the snowfields in Central and South Gully as well as at the base of the ice in Pinnacle and Odell. The northern gullies of Yale, Damnation, and North are primarily ice and contain very little snow. The Lion Head Winter Route is now open. Bear in mind this is not a hiking trail and mountaineering sense should be in your backpack, right next to you crampons and ice axe. The Sherburne Ski Trail is skiable top to bottom but is in very rough shape. Anyone care to share the story of the blood we found sprayed all over the trail yesterday? We are baffled.

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 6:15 a.m. January 27, 2016. A new advisory will be issued tomorrow.

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

2016-01-27

Avalanche Advisory for Tuesday, January 26, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human-triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: The primary avalanche problem today is windslab. After forming during the high winds almost 7 days ago, these firm slabs remain unreactive. I expect to find overall good stability around Tuckerman. However, as the total snow for the season is still low, there are areas where the slab could be thin enough to allow a person’s weight break the bridging strength and initiate a crack. These areas primarily exist where terrain features have only recently been covered, such as the Lip and Center Bowl.

WEATHER: After three days of sunny weather on the mountain, today will diverge from this trend. Temperatures are expected to rise through the morning and peak just when precipitation may start, early afternoon. Currently, at 8:00am, elevations between 2300’ and 4300’ are above freezing. What form the precipitation comes in will all depend on when it starts and how quickly temperatures drop. Forecasted amounts of rain and snow are minimal and I expect whatever falls from the sky today to have little adverse effect on the current snowpack. Winds today will be strong, gusting to the century mark by nightfall.

SNOWPACK: Over the past week, the summit has recorded a total of 0.03” SWE, delivering 0.9” of snow. Sustained, strong winds that abated on January 22 have left us with a surface layer of firm windslab throughout Tuckerman. While faceting is likely taking place beneath this bridging layer, in most places it would take a truck to create enough force to impact any weakness existing below this surface slab. That being said, the real snow has yet to arrive for the winter and there are many terrain features lying just beneath the surface that create enough hazard to require bringing your A+ terrain management game. Areas that provide the best possibilities for skiing have rather ugly looking runouts below.

Huntington Ravine remains under a General Bulletin. It is important to remember that avalanches can occur under a General Bulletin. The biggest potential areas are the snowfields in Central and South Gully as well as at the base of the ice in Pinnacle and Odell. The northern gullies of Yale, Damnation, and North are primarily ice and contain very little snow. The Lion Head Winter Route is now open. Bear in mind this is not a hiking trail and mountaineering sense should be in your backpack, right next to you crampons and ice axe. The Sherburne Ski Trail is skiable top to bottom and is seeing a fair amount of traffic. This traffic is pushing snow to the sides, revealing a good amount of water ice and rocks that had been covered. Expect challenging conditions.

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 8:15 a.m. January 26, 2016. A new advisory will be issued tomorrow.

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

01-26-2016

Avalanche Advisory for Monday, January 25, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: Today’s primary avalanche problem continues as windslab. These firm slabs, formed during the period of high winds last Tuesday through Thursday, have proved to be unreactive so far. They are thick enough in most places to create a strong bridge over the potential weak layers residing underneath. With a snowpack that is still quite shallow for late January, there are plenty of terrain features that have only recently disappeared under the snow. It could be possible to initiate a crack in these areas of thinner coverage, particularly in the steep areas of the Lip and Center Bowl.

WEATHER: Yesterday was one of those mid-winter days on Mount Washington that makes one feel as though they’re no longer in the Arctic. Sunny skies prevailed with temperatures rising into the high teens F. Temperatures look to remain in the teens through today along with decreasing winds. Some clouds will linger this morning but by afternoon they should dissipate bringing on another sunny day. A warm front is approaching with a possibility of snow for tomorrow morning and the ensuing low pressure system to produce a sharp increase in winds. Be alert for an increase in avalanche hazard for tomorrow. We have received no new snow since the sustained period of high winds last week.

SNOWPACK: Today’s low rating derives from the strength of the windslabs. This windslab, very thick in areas like Left and Right Gully, the Sluice and the Chute, is the top layer of the snowpack. Beneath this layer of pencil-hard windslab is a softer layer of windslab (primarily 1F). One potential bed surface for an avalanche is the ice crust formed two weeks prior from the rain event on January 11. With colder nights recently, faceting is taking place near that bed surface as well as within the 1F layer sandwiched in the middle. Yesterday’s and today’s milder temperatures may encourage the sintering process, though despite the bright sun, the snowpack was not heating up due to solar radiation. This all points to a surface layer of windslab that is quite strong, but there is the potential to find the thin spot where closer-to-surface faceting combined with a traveler’s weight could produce a fracture. These thinner areas are likely to found in steep terrain like the Lip and Center Bowl, areas that take much more snow to fill in.

Huntington Ravine remains under a General Bulletin. It is important to remember that avalanches can occur under a General Bulletin. The biggest potential areas are the snowfields in Central and South Gully as well as at the base of the ice in Pinnacle and Odell’s. The northern gullies of Yale, Damnation, and North are primarily ice and contain very little snow. The Lion Head Winter Route is now open. Bear in mind this is not a hiking trail and mountaineering sense should be in your backpack, right next to you crampons and ice axe. The Sherburne Ski Trail is skiable top to bottom and is seeing a fair amount of traffic. This traffic is pushing snow to the sides, revealing a good amount of water ice and rocks that were covered. Expect challenging conditions.

2016-01-25

Avalanche Advisory for Sunday, January 24, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEMWind slabs continue to be the primary avalanche problem.  Continued cold temperatures have not contributed to a trend towards stability so be aware that the hard windslabs in the Ravine could still fracture. These slabs are thick and strong in most areas of slopes like Right Gully, the Sluice, Left Gully and even lower in Center Bowl where a person would be hard pressed to find a thin spot to create a fracture. In the steepest terrain, it may be possible to trigger a hard slab given a human trigger over a thin and unsupported area or convexity.

WEATHER: Yesterday, overcast skies, calm to light winds with high temperatures in the low to mid-teens F prevailed in the Ravines. Temperatures dipped a bit in the overnight hours with clear skies and light wind leading to colder temperatures settling into the valley. A slight warming trend will bring temperatures into the 20’s F today with 15-30 mph NE then NW winds on the summit increasing later in the day. These wind speeds combined with a lack of available snow for transport will not adversely affect stability.

SNOWPACK: Weather conditions over the past 36 hours have not lead to settlement or sintering and likely have led to some faceting near our now basal ice crust a meter or more down as well as in the softer (1F) wind slab beneath our surface slab. Our low rating comes primarily from the unlikely probability of the weight of a human reaching down to one of these weak layers through the strong, hard (P) surface slab. Primarily planar (Q2) but moderate to hard shears were found in compression tests Saturday between wind slabs and above the ice crust. Currently, some of the most likely spots to find slabs that taper in thickness or are variable in size are also in the most consequential avalanche zones. The Lip and Center Bowl spring to mind where discontinuous but extremely steep (40+degrees) slope angles with complex underlying terrain may create a circumstance for triggering a hard slab. Places like Right Gully and the lower part of Sluice contain some of the thickest and smoothest slabs. Smooth, firm surface conditions may yield to a ski edge but limited boot penetration will challenge those climbing in soft boots or without crampons. Vigorous step kicking in hard boots yields small steps for the forefoot. The hazardous pile of boulders sticking out of the snow in the fall line just below the mouth of Right Gully and upper Lunch Rocks is worth noting making either of these areas an unforgiving spot to miss a turn.

Huntington Ravine, while under a General Bulletin, may harbor some wind slab issues such as at the base of Central, Pinnacle and scattered through Odell and South gullies.  Good visuals show that the northern gullies have limited snow coverage so expect to find long stretches of low angle ice.  The Lion Head Winter Route is now open and is recommended for those opting to avoid avalanche terrain in the early season. Microspikes and ski poles are good supplemental tools, but are not substitutes for crampons and an ice axe on this route.  The John Sherburne Ski Trail is passable but becomes harder each day as water ice expands and snow is raked off. Expect challenging conditions.

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 8:00 a.m. January 24, 2016. A new advisory will be issued tomorrow.

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

2016-01-24

 

Avalanche Advisory for Saturday, January 23, 2016

All forecast areas of Tuckerman Ravine have LOW avalanche danger.  Natural and human triggered avalanches are unlikely.  Watch for unstable snow in isolated areas.  Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches than Tuckerman, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: Wind slabs continue to be the primary avalanche problem.  The high winds this week have packed and battered most snow covered slopes into firm hard wind slab.  The majority of snowfields could be categorized as pencil (P) hard over softer 1 finger (1F) hardness in most locations.  This step change can be characterized as being fairly deep, often found 0.7 meters or more from the surface.  I would consider this “deep” based on the overall strength of P and P+ slabs. Current slabs can be described as mostly resistant to human triggering due to both bridging and the fairly strong bond at the hardness transition. The possibility of triggering these slabs is low, but consider spatial variability and look for some isolated instabilities in small pockets, such as near the Sluice and the traverse over to the Lip. Buried terrain features that are hard or impossible to locate like rocks and bushes may also have weaker snow around them.

WEATHER: Today’s weather won’t quite be the best we can see, but should be pleasant for winter activities on Mount Washington for the prepared.  A very light E and NE wind will gradually build today, eventually climbing towards 40 mph (64kph) late in the day.  This is coupled with a fair amount of cloud cover, but the summits are expected to remain clear with the mercury rising into the teens F.  This general theme will continue through the weekend, although winds will shift around from the W by tomorrow with a slight uptick in velocity.

SNOWPACK: Yesterday’s field assessments and analysis allowed us to drop all areas to “Low” avalanche danger in Tuckerman.  Digging, poking and prodding in Right Gully, the Sluice, the Chute, and Left Gully delivered a pretty consistent theme for us yesterday afternoon.  Firm P+ to P hard slopes near the surface, that are fairly strong, exist in the majority of locations.  As you dig you are likely to find softer snow to Finger hardness (F+ to F-) beneath, but the depths will vary tremendously as you move around.  This depth variability should cause more concern if hard over soft slabs are seen near the surface.  This is based on your weight being more likely to impact them then if found deeper. However, we found that the transitions in hardness, often considered a potential failure layer, were either deep or bonding well. We walked away feeling the overall strength of wind slabs were good, making the move from Moderate to Low avalanche danger appropriate.  Although the proverbial arrow has pointed more towards green than red, be cautious and make thoughtful choices based on data observations and not desire. Expect spatial variability and isolated pockets of instability so as always make constant assessments and risk evaluations.  A small pocket high on a route has very different ramifications generally than one that is lower.

Huntington Ravine, while under a General Bulletin, may harbor some wind slab issues such as at the base of Central, Pinnacle and scattered through Odell and South gullies.  Good visuals show that the northern gullies have limited snow coverage so expect to find long stretches of low angle ice.  The Lion Head Winter Route is now open and is recommended for those opting to avoid avalanche terrain in the early season. Mountaineering skill and proper equipment, such as crampons and an ice ax, are essential. Microspikes are not adequate for this route or any other accessing treeline.  This route opens annually when the Lion Head Summer trail snowfield traverses grow enough to become an avalanche hazard.  The John Sherburne Ski Trail is moving into survival skiing in many locations as it becomes harder each day with rapidly growing water and alpine ice. Expect challenging conditions.

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 a.m. January 23, 2016. 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

2016-01-23

Photos from January 22, 2016

Looking into the mid section of Chute from above the narrows.

Looking into the mid section of Chute from above the narrows.

AMC Caretaker on her day off. She is a dedicated and adventurous skier to ski this stuff.

AMC Caretaker on her day off. She is a dedicated and adventurous skier to ski this stuff. Though pockets of softer snow could be found, they were heavily wind affected and variable in density.

"Nope, no soft snow here either."

“Nope, not much soft snow up here either.”

An overview of the lean snowpack. Note the pile of boulders at the exit to Right Gully.

An overview of the lean snowpack. Note the pile of boulders at the exit to Right Gully. Things are certainly filling in but we could use some more gifts from above to smooth things out and fill things in. The smooth snow in the Sluice is firm “wind board”.

Chris checking for the ingredients for future buried weak layer in Right Gully.

Chris in the Sluice after checking for the ingredients for future buried weak layers in Right Gully.

Northern gullies still blown mostly free of snow. These climbs would take your average party longer than when good neve (firm snow) abounds.

Northern gullies still blown mostly free of snow. These climbs would take your average party longer than when good neve (firm snow) abounds.

Avalanche Advisory for Friday, January 22, 2016

All forecast areas of Tuckerman Ravine have MODERATE avalanche danger.  Natural avalanches are unlikely and human-triggered avalanches are possible. Evaluate snow and terrain carefully. Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: Wind slabs remain the primary avalanche problem. High winds over the past several days have forged hard slabs in most of our forecast areas. These slabs are strong and mostly resistant to human triggering but it may be possible to find the thin spot which could propagate a crack.  Where these slabs exist, especially in steeper terrain you could find a thin spot and perforate this slab, causing a section to fail. The possibility of triggering something is on the lower end of the rating but the consequences of triggering one of these thick and dense slabs is severe. Be on the lookout for hollow sounding areas in well sheltered locations.

WEATHER: Though winds will abate through the day, lingering moisture to the west will flow up and over the mountain creating fog at ground level during the morning hours. This fog will diminish as downsloping wind dries out. Temperatures are starting out in the -10F (-23C) range but will rise into the single digits above zero later on. Winds from the NW at 50-70mph (80-112kph) will diminish to the 35-50mph (55-80 kph) range. All in all a remarkably average January winter day is on tap.

SNOWPACK: Since our prolonged period of high winds began on Tuesday, we have received no significant snowfall. During this period, the summit recorded peak gusts of 127mph on Tuesday, 97mph on Wednesday, 112mph yesterday. In short, our snow pack in the Ravines, as well as the Sherburne Ski Trail, is wind hammered. The rain crust and water saturated refrozen snow and ice from a couple of weeks ago is showing in many places on the Sherburne. We’ll continue to look for this layer which may exist at some depth in certain areas of Tuckerman. In sheltered areas the crust is likely deep below a travelers stress bulb. In shallower areas, it may serve as a weak layer, but this remains a hypothetical. Other weak layers, in the form of varying slab densities, from mid-storm wind velocity changes would also be worth looking out for. Huntington Ravine may harbor some wind slabs at the base of Central, Pinnacle and scattered through Odell and South gullies but good visuals this morning show that the northern gullies have limited snow coverage so expect to find long stretches of low angle ice.

Barring some unforeseen circumstances, we will change over use from the Lion Head summer trail to the winter route starting tomorrow morning due to the growing bed surface for avalanches on the summer 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.
  • Posted 8:30 a.m. January 22, 2016. A new advisory will be issued tomorrow.

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

2016-01-22

Avalanche Advisory for Thursday, January 21, 2016

All forecast areas of Tuckerman Ravine have MODERATE avalanche danger. Heightened avalanche conditions exist on specific terrain features.  Natural avalanches are unlikely and human-triggered avalanches are possible. Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches, but understand instabilities in these smaller locations may exist.  It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: Wind slabs continue to be the primary avalanche problem.  Clouds and blowing snow continue to veil the Ravine which will limit the ability for an overall quality assessment.  Existing slabs will likely be strong and stubborn to human impacts bridging over weak layers due to very high winds in the past 72 hours.  However, expect the outer extent of some of these slabs to be thin and more prone to fracture and failure, initiating into the thicker hard slabs nearby. If this occurs expect the potential fracture to travel greater distances than in softer slabs.  Anticipate the possibility for an avalanche that could encompass the entire snowfield, only limited by terrain features such as cliff bands and ice features.  In very sheltered lee areas of W to NW winds you may find isolated softer slabs that could be easier to trigger.  These softer snowfields are only a small percentage of the overall snowpack and less of a concern than the higher consequence hard slab avalanche.

WEATHER: Full winter ice cream headache conditions continue today due to below zero F temperatures and very high winds.  Visibility is expected to increase later today and then even more tomorrow as a high pressure slides in.  Unfortunately, the storm that will slap areas south of us with multiple feet of snow shouldn’t do much for our mountains, but more on that tomorrow.  Skiing may actually be pretty good if you head into southern New England this weekend. Slight warming, as well as a significant wind drop, will occur over the next 36 hours making the mountains more user friendly as we move into Saturday and Sunday.  Expect winds to slowly taper to as low as 15mph by Friday night.

SNOWPACK: As discussed yesterday we have limited snowpack information and are basing ratings on the past several days of weather and historically like events.  Winds will stay high today, gusting into the 90’s mph (150’s kph), eventually backing off during the overnight.  However, even with the tremendous transport power of these winds there is limited snow available in the alpine zones, so generally we are on a trend of increasing stability.  Following high wind events on Mount Washington, where winds are sustained for long periods over 100mph (160 kph), the mountain is left with what we dub “Steel Slab”.  This very hard and strong slab has enormous bridging capability as well as tensile strength.  The outer edges, or occasionally mid-snowfield, are thinner and less tolerant of your weight and impact bulb.  These locations are typically the trigger locales for the adjacent stronger thick hard slabs. The spatial variability and the ability to navigate the proverbial minefield of differing slab thickness is difficult.

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 a.m. January 21, 2016. A new advisory will be issued tomorrow.

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

2016-01-21

Huntington Photos – January 20, 2016

The clouds cleared today from Huntington while Tucks was still socked in. Good visibility confirmed our suspicion that the terrain would have been scoured hard by strong winds.

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Avalanche Advisory for Wednesday, January 20, 2016

All forecast areas of Tuckerman Ravine have MODERATE avalanche danger. Heightened avalanche conditions exist on specific terrain features.  Natural avalanches are unlikely and human-triggered avalanches are possible. Lobster Claw, Lower Snowfields, and the Little Headwall are not posted due to lack of snow cover. Exercise caution in these areas.

Huntington Ravine is under a General Avalanche Bulletin. General Bulletins are issued when instabilities are isolated within forecast areas and are issued every three days or earlier if conditions warrant. Forecast areas in Huntington have less well-developed snowfields to produce avalanches. How the recent strong winds have affected snow coverage in Huntington remains to be seen. It is critical that you assess snow and avalanche conditions if venturing into Huntington.

AVALANCHE PROBLEM: If we could see into the ravines this morning, what we expect we’d see is a lot of hard wind slabs left over from the wind loading that has been taking place over the last couple days. Wind slabs are your primary avalanche problem. The size and extent of the problem will depend largely on what slopes have avalanched recently and when, which we are unable to determine as of yet due to the thick fog. The existing slabs will likely be strong and stubborn to human impacts, but if you should find the sweet spot and trigger an avalanche today, it will be in an unforgiving layer of dense hard slab. As long as winds are able to find snow to transport into the ravine, we cannot rule out the potential for a naturally triggered avalanche today. Areas such as the Lip, Center Bowl, and Chute are at the upper end of the Moderate rating.

WEATHER: It’s been a wild couple days up here weather-wise. Yesterday’s peak gust didn’t get as strong as forecast, but 117mph (190kph) isn’t bad. Persistent snowfall on Monday brought roughly 5” (7.5cm) of new snow to the summit, which has been followed by the fog and very strong westerly winds. These winds have kept blowing snow in the hourly observations at the summit for more than 48 hours straight. Today you’ll face persistent strong winds, cold temperatures, and some additional blowing snow. These are certainly are “full winter conditions.” Thankfully, we are trending toward clearing conditions which will hopefully provide some visibility this afternoon.

SNOWPACK: As mentioned, we have been unable to get even visual observations of what’s happened in the last couple days here, so we don’t have first-hand data regarding the snowpack. Looking at the weather for the last few days and the forecast, we believe we may still have wind loading taking place today as a slow shift in wind direction from the W to the NW may access snow that had settled into small lee features in the alpine zone. Surface slabs are often quite strong after this type of event, especially in areas where it is thickest. However, due to the lean coverage this year we have a lot of places where the slab may be thin enough for you to impact a weak layer, such as edges (where slabs tend to naturally become thinner) and near buried rocks or trees. Your ability to navigate the proverbial minefield will be an important factor in keeping safe. Additionally, the currently disjointed nature of our terrain can allow for some very sheltered location to harbor some softer slabs.

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 a.m., Wednesday, January 20, 2016. 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

2016-01-20