Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:00a.m., Monday, February 28th, 2011

Tuckerman and Huntington Ravines have HIGH avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely.  Travel in avalanche terrain is not recommended. The only exception to this rating is the Little Headwall in Tuckerman Ravine which has Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.

We have a high degree of confidence that today’s conditions will result in numerous natural avalanches in both Ravines.  A winter storm is forecasted to dump 7-10″ (18 to 25.5 cm) of snow and sleet in the mountains before changing over to freezing rain this afternoon.  Winds are forecasted to be out of the S, shifting to the SW and increasing to 50 to 70 mph (80 to 113 kph) during the day.  Tonight, winds will continue shifting until finding a home out of the NW and increasing  to 70 to 90 mph (113 to 145 kph) with gusts forecasted over 100 mph (161 kph).  There are a number of blatant clues telling us that snow stability will be poor today.  The snow that is falling right now is landing on yesterday’s snow that totaled around 2-3″ (5 to 7.5 cm).  Yesterday’s snow was remarkably light with a density around 4%.   This will provide an ideal weak layer for the first round of avalanches today.  As much as I hate to accept it, warm air will be nudging its way into the mountains causing today’s snowfall to increase in density and ultimately transition to sleet.   This will continue the theme of an upside down snowpack with lighter snow becoming buried by increasingly heavier snow.  Wind loading aside, this is a red flag when it comes to snow stability and will be an issue on all aspects.  I suspect these details will be subtle in comparison to the dramatic effect wind loading will have on snow stability today.  The shifting and increasing winds will transport copious amounts of new snow onto all aspects of the ravines and create wind slabs of increasing density as the day wears on.  When you put all of these variables together it is hard to figure a way that avalanches won’t occur.  The fun doesn’t end there!  Freezing rain could create some intense glazing later this afternoon which will make you wish you were wearing a house rather than your fancy parka.  Depending on how much freezing rain accumulates, some of the snow could become encapsulated by a crusty layer.  The increasing winds should do a good job at ripping this to shreds overnight but we will have to wait and see how it all plays out.  It is worth noting that today’s avalanches could step down into older wind slabs that were deposited on Friday and Saturday resulting in some sizable slides.

The warm air that will move in today will be quickly booted out by very cold air once the winds shift to the NW.  Tomorrow’s summits forecast is calling for mostly sunny skies but winds will still be quite strong and temperatures will struggle to reach the single digits F.   Aside from a minor weather disturbance on Wednesday, it looks like the rest of the week will be quiet with plenty of cold air.

Please Remember:

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

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:20a.m., Sunday, February 27th, 2011

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

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

There are two primary stability issues to focus on today.  The first pertains to wind slabs that are left over from Friday’s snow storm that caused several natural avalanches in both Tuckerman and Huntington Ravines.  The second is new snow that will continue falling into the afternoon and the potential for this new snow to form soft slabs that could push a number of areas to the upper end of their forecasted ratings.  Starting with the first concern I mentioned, Friday’s storm brought between 6 and 8.5″ (15 and 21 cm) of snow to the mountains and it was accompanied by winds that shifted counter-clockwise from the SE to the W.  Wind transported snow created unstable wind slabs and natural avalanches occurred in many of our forecast areas.  Ongoing wind loading from west winds continued into yesterday leaving wind slabs behind of varying density and size.  These wind slabs fall within the Moderate rating and it is possible you could cause one to fracture and fail resulting in an avalanche.  These can be found in just about every forecast area with the Center Bowl, Lip and Sluice being the most unnerving representatives of this stability issue.  Some areas, particularly in Huntington, have more spatial variability so good route finding skills can provide you some reasonable alternatives to climbing on this suspect snow.  That being said, limited visibility will make it difficult to pick out a good line.

The second stability issue will be developing as the day progresses.  The formation of touchy soft slabs is possible today as winds from the SW shifting to the W between 10 and 25 mph (16 and 40 kph) gently transport new light density snow into the start zones and other lee areas of the ravines.  These new slabs could be pretty reactive to people making them easy to trigger and cause an avalanche. We are expecting up to 2″ (5 cm) of new snow today which makes us comfortable with many areas being posted at Moderate.  If we exceed the forecasted snow totals some areas posted at Moderate may push into the Considerable rating due to the potential for these new slabs to avalanche on their own. This is a key piece of bulls-eye information you will need to monitor if you plan on being in avalanche terrain today.  Either way, expect to find a variety of snow out there that is waiting for you to test the balance between strength and stress of the snowpack.  The ability to evaluate snow stability and employ safe travel techniques will be important for anyone traveling in avalanche terrain today.

A significant storm is lined up to provide  us with a messy Monday.  Accumulating snow is forecasted to give way to freezing rain and possibly rain tomorrow.  Expect this miserable weather to be complimented by elevated avalanche danger in both ravines.

Please Remember:

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

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

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:30a.m., Saturday, February 26th, 2011

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

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

Whether your just heading up to the summit via Lion Head or looking to get into one of the ravines, blowing snow is going to be your greatest adversary today. Currently from Hermit Lake the view is obscured by a cloud of airborne snow; above treeline this snow is moving along at a quick pace being blown on steady 60-70mph (97-113kph) summit winds. Yesterday’s snowfall measured in at close to 6″ (15cm) of 10% density snow at the Summit and 8.5″ (22cm) of 10.5% density snow at Hermit Lake. Today’s avalanche concerns are directly related to recent snowfall and strong W and NW winds. In Tuckerman Ravine, the rate of active wind loading equates to naturally triggered avalanches being possible and human triggered avalanches being likely. This holds true for all forecast areas of Tuckerman except for the Little Headwall. This area is generally pretty small for avalanche terrain, but if you’re one of the first to test this steep slope you should know that human triggered avalanches are possible.

Huntington Ravine sits solidly at a Moderate rating today. In the recent storm a couple avalanche paths ran farther than they had yet this season, including Odell and another from either Yale, the fan, or a combination of both which ran to the stream bed in the floor of the ravine.  Most areas currently have new windslab that you’ll want to watch out for, the exception being Odell which was scoured clean but is now being reloaded. Of course, windloading should be on your mind for all areas of Huntington, though it’s not quite as intense as in neighboring Tuckerman Ravine.

The John Sherburne Ski Trail is thankful for some fresh snow. Expect some sections to be scoured out by winds and other sections to be pretty well drifted in. Remember, it is a backcountry ski trail so be prepared for the 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.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 8:30a.m., Friday, February 25th, 2011

Tuckerman and Huntington Ravines will have HIGH avalanche danger. Natural avalanches are likely and human triggered avalanches are very likely. Travel in avalanche terrain is not recommended. The only exception to this rating is the Little Headwall, which has Moderate avalanche danger. Natural avalanches are unlikely and human triggered avalanches are possible.

Today brings both good and bad news. The good news is that we’re getting snow today, and the forecast is now entirely free of the sleet that was a possibility for the midday hours. It seems like it’s been a while since we’ve had a good storm, so this will freshen things up a bit around here. The bad news is that the shift in the track of the storm means we’ll be getting less snow than was forecasted in previous model runs. Currently, the National Weather Service is forecasting 4-8″ (10-20cm) across the greater Mount Washington region and 6-10″  (15-25cm) on the higher summits, while the Observatory is forecasting 8-12″ (20-30cm) for the higher summits. Both of these are down from the previous forecasts of 10-14″, which is the bad part of the news.

Regardless of exactly how much snow we get today, the outlook for avalanche danger will remain the same. Today expect increasing avalanche danger throughout the day. By the end of our forecast period we will be firmly into the realm of High avalanche danger. Winds today will quickly whip around from the SW to the SE, E, NE, N, and finally settling into a NW flow by late evening, all the while increasing in velocity. In the early part of the storm, when winds are from the SE and E, there won’t be much in the way of direct loading, but some cross loading may occur. During this time, a weak unconsolidated layer will be laid down across much of our avalanche start zones. As winds wrap around to the NE and N, we’ll begin to see more direct loading on S-facing slopes and more cross-loading on E-facing slopes. By the time winds have moved around to the NW they will be blowing around 65-80mph (105-130kph) with higher gusts, providing ample loading in all of the forecast areas of Tuckerman and Huntington Ravines, all of which will fall on the unconsolidated snow from early in the day. In all areas the avalanche danger will be on the rise, however, due to the progressive winds, slopes with S-facing aspects will be leading the pack. Examples include North and Damnation gullies in Huntington and Lobster Claw and Right Gully in Tuckerman. Other areas will follow closely behind. I know many of you like to hit the gas pedal when the traffic light turns yellow and sneak through before it turns red. If you’re thinking of hustling up here and getting through before it gets too bad, you might be lucky enough to pull it off. But just like running a red light into oncoming traffic, trying to race the storm might lead to you getting blindsided by a force greater than anyone’s body should be subjected to. The good news of that scenario is that with the fog and falling snow you wouldn’t likely see it coming. In reality, there is nothing good about being involved in an avalanche; for this reason we do not recommend travel in avalanche terrain today.

Though you won’t find us in avalanche terrain, we’ll be monitoring snowfall closely. Winds tonight are going to continue to pick up in speed, getting quite strong by daybreak. Expect a lot of blowing snow tomorrow, and consequently elevated avalanche danger. If your plans include a trip to Mt. Washington this weekend, I’d recommend looking at our Weekend Update this evening and the Avalanche Advisory in the morning, both can be found on our website 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.
  • This advisory expires at midnight. A new advisory will be issued tomorrow.

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

Printable Advisory


Avalanche Advisory for Tuckerman and Huntington Ravines

Posted 6:30a.m., Thursday February 24th, 2011

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Lip and Sluice 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.  Isolated terrain features may hold pockets of instability in these areas.

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

The beginning of the day should start clear with sunshine prevailing this morning as the high pressure lingers over the mountains.  This will slowly transition to increasing clouds with a trace of new snow by the twilight hours.  This will wet the chops for the tomorrow’s significant weather maker as a WINTER STORM WARNING has been issued from 7am to 7pm on Friday by the NWS.  More about that momentarily, but let’s focus on today for a minute.  We continue to have some instabilities hanging on from a snowfall several days ago due to slow consolidation.  Cold temperatures and wind have kept many slopes with newly deposited slabs from warming enough to allow enough sintering to drop concerns for all areas.  Although the sunshine has allowed solar gain to help a little in a few areas heavily protected from the wind this did not occur on a widespread basis.  This was verified yesterday on south facing aspects near the Lobster Claw and Right gully by Justin who witnessed very little heat penetrating into the snowpack.  Areas of surface crust remained cool as winds pulled any solar gain off the surface before making much headway.  Therefore the Lip and Sluice remain at Moderate avalanche danger today and are the main areas to use all your avalanche skills, knowledge, and experience in as human triggered avalanches are possible.  Knowing these areas still harbor some issues locations such as Right Gully retain less instability and risk. 

These issues will become fairly moot tomorrow as 10-14” (25-35cm) of snow, with perhaps some sleet, is forecasted to slap the mountains.  The system will come from the S to SW during the initial onslaught and shift to the W increasing from an early 25-40mph to 55-65mph in the afternoon.  This is an ideal scenario to generate widespread instability on a variety of aspects and enough wind velocity to load copious amounts of snow into the Ravines.  If the storm stays on track with the expected moisture, which the models have come into agreement on, I would expect enough avalanche danger to make ravine travel not recommended.  Anticipate a High avalanche danger forecast and maybe even the “E” slat (Extreme) depending on intensity rates and timing which we will have a better handle on Friday morning.  I would also expect poor to no visibility above treeline during the storm. Currently it appears winds will ramp up Friday night into Saturday causing continued loading into the weekend.  Right now I would expect some elevated avalanche danger and some scoured areas Saturday and Sunday.  Be sure to read the avalanche advisory each day before heading into avalanche terrain.

Please Remember:

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

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

Print Friendly Avalanche Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted at 6:30, Wednesday, February 23, 2011

Tuckerman Ravine has MODERATE and LOW avalanche danger. The Center Bowl, Lip, Sluice and Right Gully have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Hillman’s Highway, Left Gully, the Chute, Lobster Claw, Lower Snowfields and the Little Headwall have Low avalanche danger.  Natural and human triggered avalanches are unlikely.  Isolated terrain features may hold pockets of instability in these areas.

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

If you are reading this as you pack the last of your goodies into your pack for today’s mountain adventure, LUCKY YOU!  You are going to be treated to a beautiful winter day with summit temperatures in the mid-teens F, decreasing winds and clear skies.  There are a lot of options for climbers with generally stable snow conditions in Huntington and a variety of snow gullies in Tuckerman that fall within the Low avalanche danger rating.  Last week we had a warm up and one dominate surface you will notice is a crusty layer that formed when temperatures fell back below freezing last Saturday.  This drop in temperatures was also accompanied by a half a foot of snow and strong winds which accounts for the other surface layers you will find today.  Strong winds blew snow into the Ravines on Saturday resulting in a natural avalanche cycle.  Since then we have had less than 1″ (2.54 cm) of new snow but persistent winds continued to find snow to transport into Tuckerman Ravine.  These recent events are the cause of existing snow stability concerns.  In areas posted at Low, such as the Chute, Lobster Claw and Lower Snowfields, you will find deposits of wind transported snow mixed in with the crusty surface.  Be aware that isolated areas of instability may still exist in forecast areas posted at Low.  The areas posted at Moderate have larger deposits of wind slab with the Lip and Sluice being the primary concerns today.  Their smooth creamy looking surface is tempting but I think they have the best potential for avalanche activity today.  The late February sunshine will remind us that spring is not too far away.  I think today’s weather will help existing slabs move toward stability in the long run.

Tomorrow’s weather won’t be quite a repeat of today’s but it is looking pretty nice.  Expect tomorrow’s stability issues to be similar to today’s with some added benefit of time and heat on south aspects.  Snow is in the forecast for Friday with light accumulation expected.  We will keep you posted on this event and how it may impact your weekend plans in the coming advisories.

Please Remember:

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

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

Posted at 8:15, Tuesday, February 22, 2011

Tuckerman Ravine has MODERATE and LOW avalanche danger.  The Chute, Center Bowl, Lip, Sluice and Right Gully have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Hillman’s Highway, Left Gully, Lobster Claw, Lower Snowfields and the Little Headwall have Low avalanche danger.  Natural and human triggered avalanches are unlikely.  Isolated terrain features may hold pockets of instability in these areas.

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

Canadian high pressure settled into the region last night and this morning we’re treated to bluebird skies and excellent visibility.  Yesterday’s winds stayed fairly constant at 45-65mph (72-107kph) as they made the shift from the WNW to the NNW.  The observers at the summit recorded blowing snow during every hourly observation until just after midnight when the winds made the move to the N and decreased slightly in speed.  Fueling this wind transport was 0.8″ (2cm) of snow that fell early yesterday morning and then light snow showers that persisted through much of yesterday but left little more than a trace.  Despite the lean amount available for transport, areas in the direct lee of the wrapping winds developed new windslab in protected locations.  These new slabs are thin in most areas but still noteworthy.  In the Lip wind-deposited snow has completely obscured the crown line that was visible Sunday afternoon.  Other fracture lines from the last avalanche cycle are still visible such as the one in the Chute and another on the climber’s right side of the Center Bowl.  Diminished concerns for natural activity have allowed some areas to drop a rating from where they were yesterday but a range of conditions still exists within each hazard rating.  I would consider the Chute and Right Gully to be on the lower end of the Moderate rating while the Lip and the Sluice are on the upper end.  The Sluice looks exceptionally smooth compared to other areas and its slopes provide some of the best protection for NNW winds. In my opinion it is the area of most concern today but also the one with the most allure.  Don’t get sucked in!

The temperatures yesterday were downright frigid and we saw lots of chilly visitors trying to make the most of the holiday.  After a drop to -17F (-27C) at the summit last night we’ll see some rebound today with highs in the upper single digits (F).  Tomorrow will get even a little warmer but for now it’s still puffy jacket time.  The snowpack is rooting for warmer weather as well because temperatures like these are not conducive to the sintering of snow crystals and the formation of bonds that are necessary for stabilization.  Until the mercury pushes a little higher the instabilities and associated potential energy in the snowpack will persist and buried crust layers will continue to inhibit vapor transport and the move toward an isothermic state.  I’m not lobbying for a spring corn cycle quite yet but a day slightly above freezing would be really nice!

Please Remember:

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

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

posted at 8:15, Monday, February 21, 2011

Tuckerman Ravine has CONSIDERABLE, MODERATE, AND LOW avalanche danger.  The Sluice and Lip have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  The Center Bowl, the Chute and Right Gully have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Hillman’s Highway, Left Gully, Lobster Claw, Lower Snowfields and the Little Headwall have Low avalanche danger.  Isolated terrain features do contain pockets of instability in these Low rated areas.

Huntington Ravine has MODERATE and LOW avalanche danger.  Central and South gully 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 except in isolated terrain features.

Falling temperatures, light snow showers and increasing winds can be expected today in the mountains.  As a low pressure system passes by we can expect a trace to two inches of snow before high pressure edges into the region, causing temperatures on the higher summits to fall to around -10 F (-23 C) with increasing NW winds that are forecasted to reach speeds of 55 to 75 mph (88 to 120 kph) with higher gusts this afternoon.  The Summit recorded 0.8″ (2 cm) of new snow as of 7 am and the radar isn’t snowing much more on the horizon.  Even though snow totals are forecasted to be light, you need to keep an eye on new snow accumulation today as it may increase the avalanche danger.  Today’s winds will be ideal for transporting new snow into the Ravines and creating new wind slabs.  Right now I expect new slab development to be in the form of isolated pockets with the greatest potential in the Bowl of Tuckerman.  If we end up with two or more inches of new accumulation expect more extensive slab development that could push some areas posted at Low into the Moderate rating.

Existing snow conditions vary widely from a crusty layer to deep slabs of varying density.  After last week’s thaw, the mountain picked up around 6-7″ (15-18 cm) of light density snow.  This was transported by NW winds on Saturday causing natural avalanches in both Ravines.  The most notable avalanches from this event occurred in the Chute, Center Bowl and Lip in Tuckerman Ravine and in South Gully in Huntington Ravine.  Early Sunday morning winds peaked over 100 mph (161 kph) on the Summit causing a number of forecast areas to become scoured out down to a crust layer that has developed from the thaw and subsequent cold temperatures.  Additional wind loading continued yesterday on lighter winds adding snow to existing slabs and creating some new ones as well.  Current stability varies greatly from one place to the next.  Left Gully, Hillman’s Highway and the gullies posted at Low in Huntington are dominated by the crust layer but you may find an isolated pocket of new snow here and there.  The Lobster Claw and Lower Snowfields are posted at Low but do have more new snow in them than the areas I just mentioned.  Good route finding skills will keep you out of trouble in these areas.  With the exception of the Center Bowl, areas posted at Moderate in both Ravines are currently on the lower end of that rating.  Larger deposits of wind slab can be found but an avalanche savvy mountaineer could find a safe route through these forecast areas though careful snowpack evaluation will be important.  As usual, the areas of most concern are in the Lip and Sluice in Tuckerman.  These have the greatest amount of wind deposited snow and have the best potential, in addition to the Center Bowl and Chute, to pick up additional wind transported snow today, adding to the current stability issues.  I expect visibility to be limited for a majority of the day.  This should factor into your route choice.  It has been a busy holiday weekend and you never know when someone will opt to descend above you putting you at the mercy of their ability to assess snow stability. 

Please Remember:

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

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

Printable Advisory

Avalanche Advisory for Tuckerman and Huntington Ravines

8:45 Sunday, 2/20/2011

Tuckerman Ravine has CONSIDERABLE, MODERATE, AND LOW avalanche danger.  The Sluice, Lip, Center Bowl and Chute have Considerable avalanche danger.  Natural avalanches are possible and human triggered avalanches are likely.  Dangerous avalanche conditions exist, therefore conservative decision making is essential.  The Lobster Claw, Right Gully and Left Gully have Moderate avalanche danger.  Natural avalanches are unlikely and human triggered avalanches are possible.  Hillman’s Highway, Lower Snowfields and the Little Headwall have Low avalanche danger.  Isolated terrain features do contain pockets of instability in these Low rated areas.

Huntington Ravine has both MODERATE AND LOW avalanche danger.  Central and South gully 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 except in isolated terrain features.

Blowing snow and low visibility were the dominate features through Saturday with some impressive gusting even though winds didn’t get extreme during daylight hours.  The air mass was thick, giving us substantial winds all the way to Pinkham Notch.  Winds pushed upwards quickly early this morning, gusting to 109mph and getting above 100mph for a few hours.  Winds are on the downhill slide but are expected to remain between 75 to 95mph a bit longer subsiding to 50-70+mph later today as a clearing trend begins.  We have had a little bit of clearing this morning but the windows were short lived especially in the Tuckerman area with some longer breaks over in Huntington.  The high winds over night did their share of scouring as we would expect particularly due to the old surface crust and yesterday’s low density snow.  Bonding between these two layers was likely difficult on exposed slopes, but in very protected lee areas from the wind I would anticipate slab with a varying degree of hardness.  This is also the case down low in the trees were snow settled once out of the high winds.   In Huntington most areas have been highly wind effected and scoured, but in areas posted at “Low” instability may be found in isolated terrain features.  The areas of most concern can be found in Central Gully above and below the center ice bulge and near the top of South Gully warranting a “Moderate” rating.   In Tuckerman poor visibility is still making it unclear what avalanched, what didn’t, what reloaded, and what is scoured.  Down low, good visibility is showing the trees between the Little Headwall and the bottom of Dead End Gully have new soft slab that is worthy of recognizing as an isolated terrain feature within it’s Low rating.  This is also the case for high in the climber’s right start zone of Hillman’s Highway.  Some areas forecasted at Moderate to highlight is the approach to both the Lobster Claw and Right Gully and the protected lees as you move into these forecast areas.  I suspect the potential for human triggers are real in these two gullies particularly the SE and E facing aspects on the climber’s left side.  The main area to have unease about is in Tuckerman’s Sluice through Chute forecast areas which have Considerable avalanche danger.  These areas have historically generated the largest slab instabilities and avalanches with the weather conditions we have seen over the past 30 hours.  Although loading should remain light today these areas have the greatest potential for both natural and human triggered avalanches.  

A few things to consider in addition to the previous stability discussion relate to the amount of traffic in the mountains right now.  The holiday weekend has brought more people onto Mount Washington than most Saturdays and Sundays which heightens the importance to make conservative decisions.  You need to be concerned about you being a human trigger for slabs under your feet as well as those below you that can’t be see through the clouds.  Flipping that around as you enter the bottom of gully someone you may not be able to see could be descending in the start zones after ascending from a different location.  When it’s busy it is a heads up day with more triggers and more people over and under one another. 

Please Remember:

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

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

Printer Friendly Avalanche Advisory

Avalanche Advisory for Tuckerman and Hutington Ravines

Posted 8:20a.m., Saturday, February 19th, 2011

Tuckerman Ravine and Huntington Ravine have HIGH avalanche danger today.  Natural avalanches are likely and human triggered avalanches are very likely.  Travel in avalanche terrain is not recommended. The only exception to this rating is the Little Headwall in Tuckerman Ravine which has Low avalanche danger. Natural and human triggered avalanches are unlikely.  Watch for unstable snow on isolated terrain features in this area.

Today’s weather is not what we were expecting twelve hours ago and avalanche conditions are a significant issue.  Yesterday we were expecting winds to reach 100 mph (160 kph) and an inch or two of snow.  Now the higher summits forecast is calling for NW winds between 50 and 70 mph (80 to 113 kph) with higher gusts.  Snowfall has proven to be higher than expected, providing the key ingredient for today’s avalanche danger.  The Hermit Lake snow plot picked up 4.5″ (11.5 cm) of snow with a density of 6.5%.  The Harvard Cabin snow plot received 4.9″ (12.5 cm) of 5% snow while the Summit only recorded 1.5″ (3.8 cm) so far.  Our field observations this morning are finding a consistent blanket of about 7″ (17 cm) of new snow in the base of Huntington Ravine and along the Tuckerman Ravine Trail below Hermit Lake.  Some additional light accumulation can be expected to add to these amounts today.  The stability issues today are pretty simple.  The new snow will be blown into the Ravines by ideal winds out NW resulting in an unstable snowpack in most forecast areas.  We expect that many paths will produce natural avalanches making it a bad day to head into the Ravines, even to have a look around.

If you plan on heading above treeline you can leave the Bermuda shorts behind.  Winter has returned and today’s temperatures are forecasted to be around 0F (-18 C) on the summits.  Even though winds speeds aren’t going to be as high as they were originally forecasted to be, 50 to 70 mph winds are challenging for us bipeds and the new snow will allow for whiteout conditions.  The recent warm weather has left an unconsolidated snowpack in the woods that hasn’t had an opportunity to freeze up yet.  If you plan on going off trail, bring snow shoes or skis.

Please Remember:

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

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

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