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

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.