Avalanche Advisory for Saturday, 1-21-2012

Expires at Midnight Saturday 1-21-2012

Tuckerman and Huntington Ravines have CONSIDERABLE avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  Dangerous avalanche conditions exist.  Careful snowpack evaluation, cautious route finding and conservative decision making is essential. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

Most importantly this morning realize we have just come down from HIGH danger last night and I believe we are at the upper end of the CONSIDERABLE danger rating for all forecast areas.  Maximum winds gusting into the upper sixties and low seventies occurred around dark last night.  This was possibly the period of highest instabilities as denser slabs were being developed in the Ravines from the west winds.  Loading this morning has slowed down substantially which makes the High rating definition of naturals being “likely” a bit over stated.  This makes the Considerable rating  of naturals “possible” more accurate.  However, an additional 1-2” (2.5-5cm) of snow today, with West winds from 30-40+ mph, will keep a threat of natural activity a potential, so be mindful of new loading rates.  The concern that stands out in my mind today is the human triggered avalanche menace.  With cold air hovering around the 0F (-18C) mark today, yesterday’s slabs have not consolidated much at all.  A building wind on Friday created soft slabs over a loose unconsolidated 3.5% snow acting as the weak layer for these new problems to fail on.  Joe and I found unstable snow near treeline yesterday during the late morning and early afternoon.  In locations that didn’t avalanche overnight I would expect a human triggered avalanche to be “likely” in new slabs.  We anticipate continued touchy instabilities across the Ravines until the clouds and new snow subside enough to see what has already avalanched and what didn’t.  A big caution with these instabilities is it’s a Saturday, so plenty of human triggers will be running around perhaps using your ascent as a decent.  Compounding this is the low visibility from clouds and blowing snow.  Some typical descents are Right Gully in Tuckerman and South and the Escape Hatch in Huntington.  Although I can’t recommend being in these locations, based on the instabilities, at all realize that additional risk may be present from above.  Obviously fresh tracks ahead of you should also scream “run away”.  It is a head’s up day!

We have switched the Lion Head ascent from the Summer Lion Head trail to the Winter route yesterday morning.  The summer trail is not recommended due to the snowfield traverses near treeline and their associated avalanche risk.  Follow the orange signs marking the route at the bottom off the Tuckerman Ravine trail and at treeline where it rejoins the summer trail above the Summer trail avalanche problems.   

 The Sherburne Ski Trail has decent coverage at this time with a fresh 6-7” of fluff. Be cautious for some buried landmines and waterbars as they still are problem particularly when you can’t see them.    

 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 8:15am. 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

 2012-01-21 Print Friendly

 

Avalanche Advisory for Friday, 1-20-2012

Expires at Midnight  Friday 1-20-2012

Tuckerman and Huntington Ravines have HIGH avalanche danger.  Natural avalanches are likely and human triggered avalanches are very likely.  Very dangerous avalanche conditions exist and travel in avalanche terrain is not recommended. This includes runout paths of avalanche activity such as the fan in Huntington and the floor of Tuckerman Ravine. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

The mountain region received a nice unexpected punch of new snow last night vastly exceeding forecasts in numerous areas.  Pinkham Notch, up to the Hermit Lake elevation has received between 6 and 7” (15-18cm) of new snow.  Here at Hermit Lake it’s still snowing with a possibility of 2 more inches (5cm) through the morning. The more significant impact of this new snow is the low densities and moderate wind speeds today.  The snow density average between our manual snowplots is 3.5% which is very light, but not surprising with temperatures below zero F in the higher elevations.  I would expect some steep areas to sluff off due to the new snow’s lack of strength and cohesion.  In “stepped” or “benched” gullies you may see some deep pillows developing.  Some potential examples of this may be found under the ice pitches in Huntington’s Central, Pinnacle, and Odell gullies or across the Tuckerman Headwall in the Center Bowl.  In addition, light to moderate winds from the S last light, moving through the SW, and over to the NW late today will load all primary aspects in the two Ravines.  While this progresses, increasing wind velocities from 25 to 60mph (40-105kph) will develop denser slabs over very loose and unconsolidated snow acting as the weak layer at the interface with the old surface.  Hard and slick surface conditions in the Alpine zone at temperatures around -5F will not hold this cold snow very well.  Therefore today’s winds will have an easy time moving new snow from above treeline down into the avalanche prone slopes of the two Ravines.   Boiling all this down to a simple statement:  I believe delicate, touchy, soft slabs will develop over loose 3.5% density snow today on most aspects from North faces early, progressing rapidly through East faces, and eventually towards the South faces.  I would expect several rounds of natural avalanche activity to occur.  Cold air falling to -10F (-23.5C) tonight at upper elevations will not help consolidate any new soft slabs instabilities that develop today.  I would expect an elevated avalanche danger in at least some areas particularly those that don’t avalanche in the next 24 hours.  Although light, 1-2” (2.5-5cm) of snow forecasted for Saturday could cause a few additional problems.

The Lion Head summer trail becomes an increasing avalanche risk each winter just below treeline, eventually being closed when we open the winter route.  We took a good look at these vulnerable traverses yesterday and they are still peppered with anchors, i.e. brush, trees, and rocks with a limited bed surface.  However this fairly unusual snowfall with very low densities has me believe that a small soft slab or loose sluff is not out of the question.  This is due to the very low strength of any new snow in the deposition minimizing the impact of anchors.  Use caution in this area and use safe avalanche travel practices such as going one at a time.

The Sherburne Ski Trail has decent coverage at this time with a fresh 6-7” of fluff. Be cautious for some buried landmines and waterbars as they still are problem particularly when you can’t see them.   Check out the Weekend Update issued late in the day for any updates and tidbits we can pass along for your weekend trip planning.

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 8:40am. 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

2012-01-20 Print Friendly

Avalanche Advisory Thursday 1-19-2012

Expires 12:00 midnight, January 19, 2012

Tuckerman and Huntington Ravines have LOW avalanche danger.  Natural and human triggered avalanches are unlikely EXCEPT IN ISOLATED TERRAIN FEATURES. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

The mountains are basking in the sun’s glory this morning albeit a rather chilly start at dawn.  Temperatures overnight inverted as winds died down and the cold air aloft dropped into the valleys.  By the time daylight rolled around the base of the mountain was colder than the summit with a temperature of -5F (-20.5C) at Pinkham Notch.  If you have the right gear for being in the mountains with cold air today you will be treated by copious sun, beautiful vistas and low wind speeds from the SSW at 10 to 25 mph (16-40kph).

Very high winds over the past 2 days have done the job scouring the mountain of available snow and packing it into the nooks and crannies where protected from the wind.  This wind was associated with some upslope snow showers that generated under an inch of snow.  Generally speaking we have widespread hard scoured slopes in the two ravines and numerous locations showing crust.  An interesting snowpack development to watch for is some intense faceting under the most recent crust.  Facets will continue to grow with today’s cold clear air.  I would expect crusts to erode and lose strength as they become cannibalized by new crystal growth.   This will be something to consider during the next loading event.  A few locations have some new snow in the strong lee particularly in Tuckerman Ravine from the Sluice over to the Chute.  If you were hunting for avalanches and spent the day trouncing all over the Ravine you would likely find an unstable pocket or two, but generally these are easy to avoid by paying attention and sticking to hard old surfaces.

Later today winds will be on the increase, building to 25-40mph (40-65kph) with clouds moving into the region.  Snow will begin very late in the day, forecasted to accumulate by Friday morning in the 2-4” (5-10cm) range on winds from the S shifting to the WNW.  Escalating speeds overnight will load new slabs into both ravines overnight if the forecast plays out.  Expect an increasing avalanche danger overnight with elevated ratings beyond today’s Low danger advisory.  This will all transpire during the presence of cold air in the zero to -5F (-18 to -21C) range which will likely produce both low density snow and slabs that will retain their instability into the weekend.  Stay tuned and check tomorrow’s avalanche advisory.  

 The Sherburne Ski Trail has decent coverage at this time. You don’t need to work too hard to avoid exposed rocks, but you may see a couple. In addition, the breakable crust is a bit arduous under ski so expect some challenging conditions until more snow comes in.

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 8:35am. 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

2012-01-19 Print Friendly

Avalanche Advisory for Wednesday 1-18-2012

This advisory expires tonight at midnight.

Tuckerman Ravine has Moderate and Low avalanche danger. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Right Gully, Left Gully, and Hillman’s Highway have Low avalanche danger. Natural and human triggered avalanches are unlikely. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

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

There are some stability concerns to be thinking about today, but you might have a challenging time getting to them. Winds today will be gusting from the W to speeds over 100mph (160kph) for most of the day. This will make travel into either ravine difficult enough, but to up the ante, temperatures will fall throughout the day reaching around -5F (-21C) at the summit. Much of the avalanche terrain in the Cutler River Drainage is scoured down to stable snow, thanks to sustained overnight winds peaking at 129mph (209kph). The areas posted at Low danger today are those where this has happened. The exception to this is Right Gully. There is a general lack of snow in the gully, except one large patch on the climbers left side just above the mouth of the gully. Here, the Low rating is more due to this being an isolated pocket within the forecast area than due to scouring.

The locations posted at Moderate today have been the most protected from the strong winds. Last night about an inch of frozen precipitation fell on the mountain while light upslope snow is currently falling. The combination of new snow and the strong winds transporting snow from elsewhere on the mountain is creating a loading situation. I expect any new slabs that will develop in the early hours of today to be dense and strong. It’s often difficult for a person’s impact on a hard slab to be enough to initiate a fracture and failure of the slope, but remember that snow stability is a balance of strength versus stress. When a slope is actively loading it is nearly impossible to accurately assess how this balance is playing out. If avalanche activity occurs today, it would not surprise me if it were naturally triggered from new loading this morning. Saying this, I don’t believe this hazard warrants a greater rating than Moderate. When wind loading comes to a close and skies clear out, it also would not be too much of a surprise to find generally good stability in many of the Moderate rated areas.

 The Sherburne Ski Trail has decent coverage at this time. You don’t need to work too hard to avoid exposed rocks, but you may see a couple. A light amount of new snow under a thin breakable crust will keep your edges on the old surface.  January 20th looks to be the turning point this winter—if not for the winter at least there may be some fresh snow for the weekend. Let’s hope for the best with this one.

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 8:250am. 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

2012-01-18 Print Friendly

Avalanche Advisory for Tuesday, 1-17-2012

This advisory expires tonight at midnight.

All forecasted areas of Tuckerman Ravine will have Considerable avalanche danger. Natural avalanches are possible and human triggered avalanches are likely. The only exception to this is Right Gully which has Low avalanche danger. Natural and human triggered avalanches are unlikely except in isolated pockets. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

Huntington Ravine will have Considerable and Moderate avalanche danger. North and Damnation Gullies have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas will have Considerable danger. Natural avalanches are possible and human triggered avalanches are likely.

Incoming weather later today is driving today’s forecasted ratings, so it’ll be a good day to get an early start and to not be out after dark in the ravines. Another weather system reminiscent of December is coming, beginning with snow through the afternoon, then warm temperatures will change this over to sleet before the day is done. Rain will eventually fall in valley locations since temperatures will be above freezing. I don’t know about you, but this is enough to make me want to bang my head off the wall a few times. With any luck, the bulk of the precipitation here will be in the form of snow. The forecasted total of 2-4” (5-10cm) will be very dependent on when the warm air is able to gain the upper hand. With SW winds in the 25-40+mph range (40-65kph), the early snow will load into soft slabs in the upper portions of many areas, notably those with a N or NE aspect. Areas with an E aspect will see some cross-loading as well (e.g. the Center Bowl and Lip or Central and Yale). The potential for sleet falling onto newly developed softer slabs creates the possibility of naturally triggered avalanches. Similarly, if you find yourself plodding your way through new soft snow near the gully tops, you might want to start thinking about finding older snow to climb on.

Today’s weather forecast is a tricky one. There is a good chance that for the better part of today not much snow will fall. So until snow is able to accumulate, the danger level will be less than the forecasted ratings. We spent a lot of time in Tuckerman yesterday and found an interesting variety of conditions. In all areas from the Chute to the Sluice, we found an upper layer of hard windslab sitting on top of lighter density layers. In the thickest locations the slab had a lot of strength, but where it was thinnest near the edges there was a noticeable weak layer and lots of elastic energy. Overall the ravine still has typical early season snow coverage and is very much broken up by ice slabs, rocks, and small terrain features. If you’re out in Tuckerman early today before snow falls, you should be expecting fair to good stability with some locations being slightly worse. It changes quickly as you move around so stay alert.

Tonight the mountain will rage once more. Winds are expected to easily exceed 100mph while temperatures freefall into the negative numbers Fahrenheit. Wednesday will be another blustery arctic day, making above treeline travel very challenging.

Please Remember:

  • Safe travel in avalanche terrain requires training and experience. This advisory is just one tool to help you make your own decisions in avalanche terrain. You control your own risk by choosing where, when, and how you travel.
  • Anticipate a changing avalanche danger when actual weather differs from the higher summits forecast.
  • For more information contact the Forest Service Snow Rangers, the AMC at the Pinkham Notch Visitor Center, or the caretakers at Hermit Lake Shelters or the Harvard Cabin.
  • Posted 8:10am. 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

2012-01-17 Print friendly

Avalanche Advisory for Monday, 1-16-2012

This advisory expires tonight at midnight.

Tuckerman Ravine has Moderate and Low avalanche danger today. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Right Gully, Left Gully, and Hillman’s Highway have Low avalanche danger. Natural and human triggered avalanches are unlikely. The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

 Huntington Ravine has Moderate and Low avalanche danger today. Central and Pinnacle have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely.

It’s another cold clear morning on the mountain and this will be the case at least for the start of the day. Currently, winds are so light that you might find yourself wondering if you came to the right mountain. Hang around a while and you’ll see Mt. Washington’s famously changeable weather. During daylight hours, clouds will build in, winds will increase, and temperatures will rise dramatically late in the day as a warm front works its way toward us. With any luck, this will give us an all snow event, but I’d not be surprised to see some wintry mix fall from the sky on Tuesday.

Snow stability and forecasted ratings are the same today as they were yesterday. Cold temperatures prevent existing slabs from settling much, so what there was for elastic energy yesterday will be there today as well. The potentially unstable slabs to be on the lookout for were deposited in the most protected lee areas after very strong W winds on Friday night. In Tuckerman, the best chances to find these instabilities would be in the Sluice, down under the Lip, near the traverse section of the hiking trail, and out under the ice in the Center Bowl. In Huntington you’ll find wind loaded snow in the climber’s left side of Central Gully, and in Pinnacle, be cautious of the snow slope below the first pitch of ice. Expect much of the snow in the ravines to be hard and wind-effected, particularly in Huntington or the more wind-exposed areas of Tuckerman such as Left Gully. If you find yourself in areas of softer snow or are punching through a shallow dense layer into a softer layer underneath, the little warning bells in your brain should start sounding.

Despite the calendar date, the Lion Head Summer Trail is still the one to use. We’re monitoring snow conditions on the trail and will open the Winter Route when avalanche potential threatens 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 7:30am. 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

2012-01-16 Print Friendly

Avalanche Advisory for Sunday, 1-15-2012

Tuckerman Ravine has Moderate and Low avalanche danger today. The Sluice, Lip, Center Bowl, and Chute have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. Right Gully, Left Gully, and Hillman’s Highway have Low avalanche danger. Natural and human triggered avalanches are unlikely The Lobster Claw, the Lower Snowfields, and the Little Headwall are not posted due to an overall lack of snow. Forecasts for these locations will begin when conditions warrant.

Huntington Ravine has Moderate and Low avalanche danger today. Central and Pinnacle have Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible. All other forecast areas have Low avalanche danger. Natural and human triggered avalanches are unlikely.

It’ll be a cold clear day on Mt. Washington; Canadian high pressure is the reason. Expect very cold temperatures with increasing wind speeds in the afternoon. With these conditions, snow stability today will remain static. I don’t expect conditions to change much during the day, for the better or the worse. What we have for stability concerns are leftover from the 9.4” that fell on the mountain Thursday and Friday and the strong winds that followed. The wind loading during this event caused numerous avalanches around the mountain and left behind a mix of conditions. Within each area rated Moderate today there are specific terrain features where a person might trigger an avalanche. These are the in strongly protected lee areas, such as under the ice in the Center Bowl, in the Lip, and under the ice in the Sluice. Some of the areas of greatest concern generally follow the path of the Tuckerman Ravine summer hiking trail. This goes up above Lunch Rocks to the Sluice and then traverses high across the Lip area. I’d also include the lower part of the Lip and across into the Bowl, as well as pockets of loaded snow in the mouth of Right Gully and in the skiers’ left side of Left Gully. In all these areas, the weak layer to worry about will be one of the many interfaces between different layers of windslab.

In Huntington much of the terrain got pounded pretty hard by the 100mph+ winds on Friday night. Clearing skies yesterday afternoon allowed us good views into the ravine, and we saw a mix of blowing snow, fractures, debris, and wind-hammered snow. Central and Pinnacle were the two gullies that refused to give reason to drop their ratings to Low. Central has significant wind loading up against the rock on the climbers’ left side. In Pinnacle I’d be most cautious with the approach to the ice, since strong winds tend to push the snow down toward the base.

As always on busy holiday weekend, there are a lot of potential human triggers running around the mountain. Pay attention to what others are doing and don’t assume that they truly know what they’re doing. If you’re interested in what we’ve seen for avalanche activity, check our Facebook page later today. I’ll try to post up a summary soon.

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 8:20am. 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

2012-01-15 Print Friendly

Avalanche Advisory for Saturday, 1-14-2012

This Advisory expires tonight at midnight.

Tuckerman and Huntington Ravines have CONSIDERABLE avalanche danger today.   Natural avalanches are possible and human triggered avalanches are likely.  Dangerous avalanche conditions exist.  Careful snowpack evaluation and conservative decision making is essential.   Some areas are not yet posted due to the overall lack of snow. These include the Lobster Claw, the Lower Snowfields, and the Little Headwall in Tuckerman and the Escape Hatch in Huntington. Forecasts for these locations will begin when conditions warrant.

We started yesterday with some interesting mid-elevational warm bands encompassing both Ravines.  Temperatures quickly spiked from the freezing point around 5 am to 35F (2C) and back to freezing all within a 3-4 hour window.  As this occurred light precipitation fell, vacillating back and forth between wet snow and light rain eventually adding up to 2.7” (7cm) with a water equivalent of 0.42” (10mm) on the summit.  The periods of freezing rain and mixed precip account for the high water content. Temperatures dropped, changing all new precipitation to dry snow and limiting the development of crust at the mid-elevations.   Winds were reluctant to wrap from the SE to the W as forecasted, but did so eventually late in the day and then raged like a tempest during the overnight. Winds peaked between 8 and 11pm Friday night with a maximum of 110mph (176kph) from the W.  Velocities have diminished, currently gusting to about 70 mph, and are slowly moving from the W to the NW.  Speeds are expected to drop just a bit more along with the temperatures which are expected to fall to -10F (-24C) through the day.

As winds finally shifted and increased last night large volumes of snow were delivered by the “Western Express” hitting the century mark over a 4 hour period.  Undoubtedly, some terrain in the lee saw some natural avalanche activity, others saw some scouring, and some saw both.  Since midnight winds have diminished but continue to transport snow from the alpine zone into the Ravines. This is in addition to upslope snow showers that are mixing into our loading situation.   Because the Ravines are engulfed in clouds and blowing snow we cannot confirm what has avalanched, what is still loaded, and what has become scoured.  With new additional loading through at least the morning, we cannot rule out the possibility of natural avalanche activity hence the “Considerable” rating.  Additionally, I believe a fair degree of spatial variability exists due to the blend of scouring and loading that has occurred.  The rating definition for human triggers being “likely” takes second fiddle to our unease for natural avalanches that may come from above.  You may be on hard old surface down low on your route with no chance of triggering an avalanche, but above you in a strong lee slope loading may release a natural avalanche.  This issue is compounded by low visibility this morning not allowing you to see the entire route.   The dynamic conditions that have transpired over the last 24 hours have clearly created some unknowns, so it will behoove you to be conservative with your choices until new facts come into play.  Once clearing occurs we may be able to ascertain more of the conditions the Ravines are currently holding secret.

Travel above treeline over the next couple of days will be rugged as full conditions will prevail.  Winds will continue to drop a bit into tomorrow but temperatures will fall to about -20F by Sunday morning.  Above treeline travel will need a high attention to detail and preparedness.  The best arctic mountaineering equipment is necessary for safe travel.  Mittens, goggles, facemasks, excellent double boots, insulated water bottles, insulated over parka, etc. are all items we have seen lacking in past accidents.  As in avalanche terrain, be conservative and remember if you make the summit you’re only half way home.

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 8:20am. 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

 2012-01-14

Avalanche Advisory for Friday, 1-13-2012

Expires at Midnight 1-13-2012

Tuckerman and Huntington Ravines have HIGH avalanche danger today.  Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended due to very dangerous avalanche conditions. Some areas are not yet posted due to the overall lack of snow. These include the Lobster Claw, the Lower Snowfields, and the Little Headwall in Tuckerman and the Escape Hatch in Huntington. Forecasts for these locations will begin when conditions warrant.

The Snow Rangers are happy again due to yesterday’s snow, snow overnight, and snow today.  We are currently coming to the tail end of one system and getting ready for another snow shot from another, with an additional 3-5” (7.5-12.5cm) forecasted for today.  This is in addition to the 6.7” (17cm) the summit received as of midnight and snow every hour since that collection.  Quite plausibly, we could end up with about a foot (30cm) of snow in the previous 36 hours by dinner time today.  Snow was brought in on winds mostly from the E, which was a bit off from the expected SE, on Thursday and very early this morning.  This crossloaded a number of aspects that face towards the S and N.  This includes areas in Right Gully, Left Gully, and Hillman’s Highway in Tuckerman and North, Damnation, Yale, and South Gullies in Huntington.  Notice we added Right Gully to the daily forecasts today.  We have not see it since this storm commenced, but due to historical knowledge, the crossloading it received yesterday, and what it will receive today it has enough bed surface area and diminishing anchors to harbor avalanche potential. 

Over the past couple of hours winds have walked rather quickly from the E over to the SW and then back a little towards the S.  A directional trend towards the W will take over this morning which will start moving yesterday’s snow in the more typical direction, directly into the Ravines. Winds will move to the WNW late today and come from the NW by morning.  Thursday’s storm snow on the ground above treeline and new snow falling today will be delivered on increasing velocities moving from a current around 40 mph (64kph) to over 70 (112kph) this afternoon.  These are ideal conditions to create new unstable slabs and natural avalanche activity.  The wind speed ramp up will generate denser harder slabs over a bit lighter early slabs that developed on lower wind speeds.  Some bulls-eye points and key issues to remember today:

  • We are on an increasing avalanche trend with rapid developing instabilities this afternoon as winds increase from the W to 70+mph.  
  • Winds will pick up snow on the ground above treeline and mix it with new snow, forecasted between 3-5”, moving a high volume of snow into both Ravines.
  • Expect very low visibility in the Ravines and above treeline.
  • Travel in avalanche terrain is not recommended due to very dangerous avalanche conditions.

The other big news is the front that will be moving into the Mount Washington region after dark producing winds gusting as high as 110 mph (176kph) and dropping the mercury like a rock getting into the -5F (-21C) area.  These extreme wind speeds will move a tremendous volume of snow into the lee east facing flanks of Washington.  Likely causing some avalanche cycles overnight and producing a wide amount of variability in snow conditions tomorrow.  Expect slopes and gullies to be both scoured as well as loaded depending on locale by daylight on Saturday morning.  Tomorrow winds will subside, but we could see the coldest air of the season staying firmly in the negative numbers for the weekend.  Many excited mountaineers and mountain travelers are coming to the hills for the long holiday weekend.  If you’re one of them be prepared with excellent winter clothing and skills.  The most common issues we see are inadequate footwear, mitts, head, and face protection.  

Be sure to check back for the most recent avalanche advisory Saturday morning and read our Weekend Update that will be posted early tonight at www.mountwashingtonavalanchecenter.org

 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 8:35a.m. Month Year. 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

1-13-2012 Print Friendly

Avalanche Advisory, Thursday 1-12-2012

Expires at Midnight 1-12-12

Tuckerman and Huntington Ravines will have HIGH avalanche danger today.  Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended due to the developing very dangerous avalanche conditions. Some areas are not yet posted due to the overall lack of snow. These include the Lobster Claw, Right Gully, the Lower Snowfields, and the Little Headwall in Tuckerman and the Escape Hatch in Huntington. Forecasts for these locations will begin when conditions warrant.

Finally, a winter storm for the mountains!  We are expecting 6-12 inches today depending on the exact track and cold air infiltration moving into the system.  Very cold air to the north mixing with the low pressure coming from the south should keep precipitation all snow in the higher mountains and particularly in the Presidentials.  Snow is being brought in on winds from the SE currently around 30 to 40mph (48-64kph). Velocities are expected to ramp up into the afternoon eventually getting to 70 mph (112kph) with higher gusts.  This will occur during and after periods of heavy snow at S-2/3 intensity rates (2-3cm’s an hour).  All of this together makes it clear new snow loading will generate unstable slabs creating an increasing avalanche danger.  Aspects with a northerly component namely portions of Hillman’s Highway, Left gully, South Gully and Odell should reach the forecasted avalanche danger rating first.  These areas will be followed soon there after by slopes facing the east that have some terrain features adjacent to them.  These locations will be cross loaded by SE winds so expect the protected lee to have building instabilities as well.  Areas pointing directly into the wind such as the Sluice, Yale, and Damnation will struggle to reach the “High” rating. 

The forecasted snow totals are pretty wide for the higher mountains, 6-12” (15-30cm). Forecasting avalanche potential for 6” is obviously different than 12” and would generate different rating choices within the 5 scale rating system.  To assure we don’t under rate the danger level, today’s postings are with the expectations that we end up on the upper level of accumulations, 9-12” (23-30cm).  Forecast areas will move quickly to the lower end of “Considerable” and climb through the rating during the morning and be bumping against the “High“ rating if we receive the aforementioned snow amounts associated with the max wind speeds of 70+mph (112kph).  Although we are most concerned about daylight hours we are taking into account the period of maximum instability that will occur after dark.  So to summarize, we will be in an increasing avalanche danger trend from now until after dark with the potential for natural avalanches beginning later this morning and becoming likely later in the day.  Keeping a close eye on snow totals today is the critical bulls-eye factor to track.  If we end up in the 6” range the “High” ratings will not be reached.

Winds will shift from the SE to the W overnight and into the tomorrow gusting over 75mph (120kph) along with a drop in temperature.  Additional snow from a secondary system is also expected to deliver another 3-5” (7.5-12.5cm) tomorrow.  I would expect an elevated avalanche danger into the holiday weekend.  The mercury should continue to drop well below zero into Saturday and Sunday so any slabs developing over the next 48 hours will likely retain their elastic energy deep into the weekend.   Be sure to check back for the most recent avalanche advisory and our Weekend Update that will be posted early Friday evening.  

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 8:40am.  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

1-12-12 Print Friendly