Petermann's Progress
    By Patrick Lockerby | September 19th 2010 02:23 PM | 87 comments | Print | E-mail | Track Comments
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    Retired engineer, 60+ years young. Computer builder and programmer. Linguist specialising in language acquisition and computational linguistics....

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    Petermann's Progress

    The huge ice island which calved from Petermann Glacier on August 4th was stuck in the mouth of Petermann Fjord for quite some time.  As I had suggested, it did not get into Nares Strait as a single ice island.  It broke into two main parts: Petermann 2010-A and Petermann 2010-B

    Petermann Ice Island 2010-B

    Petermann 2010-B moved at a fairly rapid rate along the strait.  There are many wind and surface current eddies, so it appeared to me to be likely that Petermann 2010-B would ground itself if it moved inshore enough.  I overlooked two factors which could work to keep the ice island away from the shores.  The first is the presence of substantial quantities of sea ice.  Any tendency of the ice island to move inshore would tend to compact the sea ice into an obstacle.  That compacted ice would tend to deflect the ice island towards mid channel.  The second factor is an underwater pressure effect.  When a floating body moves towards shallow water it tends to produce a pressure wave between itself and the bottom profile.  If the force tending to propel the floating body onto the shoal is too low, the pressure wave deflects the floating body horizontally and keeps it from running aground.

    Petermann 2010-B in Smith Sound - Sept. 19 2010
    image source:

    This ice island will run aground when a strong enough wind and current combination pushes it into a bay or a fjord estuary.  If sufficient sea ice compacts to seaward of it then the ice island will almost certainly stay put until next Spring.

    Petermann Ice Island 2010-A

    This ice island has just moved away from the place by Joe Island where it has been trapped for some time.  It rotated anti-clockwise around Joe Island.

    Petermann 2010-A in Nares Strait - Sept. 19 2010
    image source:

    Petermann 2010-A in Nares Strait - Sept. 19 2010
    image source:

    Newly frozen ice in Petermann Fjord
    image source:

    Petermann 2010-A was probably dislodged by a combination of factors.  A spring tide is only a few days away, so tides will already be significantly higher than average.  The flow of floes coming from Lincoln Sea will have provided a sequence of nudges tending to rotate the ice island.  The presence of leads across the newly frozen sea ice in Petermann Fjord is strongly suggestive of winds coming down the fjord.  All of these factors coming together seem to have been just enough to tip the balance and rotate the ice island clear of Joe Island.

    If this section stays in the middle of Kennedy Channel and runs into Hans Island then the momentum will be enough to break the ice island into more sections.  Depending on the orientation, the impact - if it happens - could produce four separate sections.

    Further calving prospects.

    Now that sea ice is forming in the fjord the chances of a further large calving before spring are becoming ever more remote.

    Next year there will be 250 km2 more open water surface in Petermann Fjord than this year.  The glacier tongue is already being eroded from beneath by warm water penetration.  With 250 km2 of extra insolation and less ice, there appears to be a positive feedback available.

    If, as I expect, the next large calving takes place in spring 2011 then there will be even more open water and even less glacier tongue to melt.  In a generally warming Arctic, the warm water flow from Nares Polynya into Petermann Fjord will be slightly warmer.  The open area formerly occupied by ice - perhaps 350 km2 by midsummer 2011 - will absorb more heat from the sun.

    The glacier tongue is not well bonded to the fjord walls.  The broken ice melange at the margins appears to be more prone to melt.  The ice tongue will be exposed to warm water melting at its new calving front, its underside and its margins.


    Given the combination of factors acting as positive feedbacks to further ice loss, the retreat of Petermann Glacier's ice tongue may well accelerate.  This year, the retreat has been about 25%.  I fully expect that by next summer that figure will have risen to 30% - 35%.

    In the absence of global warming the ice tongue might retreat, say, 50% and then slow or reverse the trend.  From the trends we are currently seeing in the Arctic generally I do not expect to see a halt to this calving process.  It is more likely, I suggest, that the tongue will have lost 50% of its 2009 length by the end of 2012.  Positive feedbacks could cause retreat to the grounding line by about 2015 to 2016.

    Previous articles on Petermann Glacier and ice islands:

    Arctic Newsflash! Petermann Ice Tongue Loses Huge Chunk
    The Anatomy Of A Discovery - Petermann Glacier Ice Tongue Calving 2010
    Petermann Glacier Calving 2010 - Update
    Petermann Ice Island Revisited

    Petermann Ice Island - Now There Are Two


    Thanks for the update, Patrick! Always open with the Lead "Petermann 2010-A Adrift!"

    I wonder if you could illustrate where the grounding line is for the remaining Glacier?

    As always, best wishes for a continued speedy recovery!

    Lodger: I spent hours on edits wondering why the article didn't look quite right.  You have pointed your finger straight at the problem:

    I didn't lead with the most newsworthy item! 

    I guess I need to ask the quack to increase the dosage of Professor Pink's palatable purple palliative pills for pale people.  :-)

    Petermann Glacier grounding line.

    That's a close approximation from memory.  I have a more accurate image in a pdf somewhere - I'll have to dig around.
    Patrick when I saw the large oval ice floe coming down near the Petermann B I wondered if there would be some interaction between them. The day after it passed Petermann B moved.

    I meant A not B of course.

    Phil: you could be onto something.  That giant floe has survived intact for quite a distance, which suggests that it is older, thicker ice.  It will be creating quite a lot of turbulence in the water as it moves, and that could have added another nudge to Petermann 2010-A.
    I can see the **** **** giant floe in the September 11th aqua image, but I was never able to pick it out of the Lincoln Sea radar images (see post on September 13th "Petermann - Then there were Two" page) to figure out where it came from. Prior aqua and terra images show a lots and lots of cloud cover, so I was not able to trace it.

    Can anyone with better eyes figure it out?

    I miss all the fun - Go on the road for a few days and Petermann-2010A escapes while I'm not around to see it!

    Here's an odd thing - you are right that it rotated anti-clockwise around Joe Island, but before it did that it suddenly rotated clockwise for a couple of days, which brought it into position where it could escape. I'm curious as to why. Looking at a sequence of satellite shots:

    10th -
    11th -
    13th -
    14th -

    you can see that it suddenly turns about 135 degrees clockwise over the course of three days, pauses for a few, and then starts turning back the other way. I can understand the anticlockwise motion - the ice flowing down the Nares Strait would produce this. But why the intial turn?

    The only thing I can see of relevance is a sudden clearing of the loose ice near the claving front of the Petermann Glacier (most evident when comparing the 11th and the 13th). But was that a cause or an effect?

    I think we just saw something quite strange...

    FrankD: many thanks for those links - I missed seeing those images.

    It looks like the flow of floes from Lincoln Sea swung into Petermann fjord, nudging the ice island clockwise.  This unhooked the ice island from Joe Island.  It seems that Joe Island was in a notch, tending to lock the ice island in place.

    I've made a quick-and-dirty animation from the images you kindly linked:
    Are we awake? I think the whole world is asleep as to what we are facing. (Yes I did read your comment on Nevin's blog)

    I do appreciate you willingness to predict. Nature has a way of making fools of us all, yet you have called so much correctly. I do not think I would bet against you.

    All the best

    Thanks for the comment, Tony.

    Nature has a way of making fools of us all ...

    ... when Nature hath made a fair creature, may she not by Fortune fall into the fire?
    W. Shakespeare - As You Like It, Act 1 scene 2.

    Had you bet against me on NSIDC end of season extent you would have won plentiful quatloos.
    Great update. Too bad Petermann-B probably won't reach Baffin Bay before the circumnavigating Norwegians and Russians, or they might have taken a picture.
    Neven: our brave friends have just done the ice-surf through Bellot Strait.

    The tidal current picked up as we approached the exit of the strait, and by the end we were doing 10 knots.

    10 knots for that trimaran is like 50 mph downhill on a bicycle: it's fun, but you need to be paying attention!

    If Petermann-B doesn't run aground then our friends may pass within 'camera distance' of it as they cross Baffin Bay to the coast of Greenland.
    Patrick, first of all, good to see you back. And thanks for the kind words about hating me. :-)

    If Petermann-B doesn't run aground then our friends may pass within 'camera distance' of it as they cross Baffin Bay to the coast of Greenland.

    Do you really think this is possible? I had just accepted the fact that Petermann-B was moving too slow for a rendez-vous.

    BTW, is this Petermann-B:

    thanks for the kind words about hating me. :-)

    You are entirely welcome, Neven. 

    Yes, that's Petermann-B.  I had downloaded the MODIS image, but you beat me to the punch in posting it - as so often. ;-)

    There is a very good chance that the ice island will go aground in the bay just ahead of it.  You can see how the ice is being pressed inshore there.  However, if it continues into Baffin Bay it will probably take about the same time to drift over to the area of Lancaster Sound as it will take our friends to sail to Baffin Bay.

    All we need now is for some brave soul to shin up the mast with a camera and a spectacular photo could be the prize.

    Petermann 2010-B still rotating and moving, but getting closer to Ellesmere Island.

    Hi Patrick, nice analysis your doing, in a very readable and still quite scientific way. I can tell your a "pro", and this is well appreciated, but that's not the way to attract comments. For that to happen you have to crack the "code of Neven", I say no more upon this topic, but there is ROOM for you both, at least in this space!

    Hope for a speedy recovery, whatever your run into. Would be such a pitty not having you around, with your "icecold" predictments.

    Now topic:
    "Drastically retreating:
    The calving rate will increase as the glacier retreats from the shoal into the deeper fjord just cleared by the glacier during advance. The water depth initially increases as the glacier retreats from the shoal, causing every more rapid glacier flow, calving and retreat", wikipedia.

    The question then is obvious: What's the depth below the remaining Peterman outlet, is that charted? History from similar tidewater glaciers tell of retreat taking place for decades on row (Muriel glacier, Columbia glacier etc.), and they actually tend to speed up the calving, another fascinating factor to be closely followed the next years!

    Christoffer: my comment on Neven's blog was very much tongue-in-cheek.  I simply couldn't handle over 130 comments for a single article - especially being a bit unwell at the moment.

    There is most definitely room for both blogs - the sly 'digs' are just an 'in joke'.  :-)

    I think your questions are answered by Will Crump, below, but I'll try to respond if you want to discuss further.

    Thanks for your input.

    Some additional information about the Petermann fjord and the sea area just outside the entrance to the fjord which is known as Hall Basin (part of the Nares Strait). The water depth at the entrance to the fjord is between 350 and 450 meters due to a sill.

    I had to look up what a sill was, and I am not sure I have this right, but in this case it appears to be a layer (sills can be horizontal or vertical) of solidified magma that has intruded (I think this means it has squeezed or pushed its way between existing rock layers) into a crack or fault zone between older rocks. Unlike a volcanic flow occurring at the surface or on the ocean floor, the magma in a sill cools while it is underground and surrounded by crust material.

    The Hall Basin reaches a depth of 800 meters and is met in the north by Robeson Channel. The channel is separated in the north from the Lincoln Sea by a sill that is 290 meters down and in the south is separated from Baffin Bay by a sill that is 220 meters down.

    The contours of Hall Basin can be found in an article titled: "Seismic Reflection Profiles from Kane to Hall Basin, Nares Strait: Evidence for Faulting" that has several interesting maps and diagrams (some of which can be understood, however, I do not understand the geological jargon in the article)

    The Petermann fjord is deeper than the Hall basin at 1100 meters. Based on the side view diagram of the fjord provided in figure 13 (last page of article at: ), the fjord quickly reaches this depth after the sill separating it from Hall Basin and maintains this depth until the fjord bottom rises at the grounding line of the glacier.

    I hpoe this answers your question.

    Patrick: My posting skills are weak. You may want to include the diagram in a future post if that is permissable.


    You may be overly pessimistic in predicting a retreat of the glacier back to the grounding line. This glacier appears to have a very different structure from Jacobshavn and other glaciers and their history may not be a good predictor of the future of the Petermann glacier.

    You also may be overestimating the effect that warming of surface waters in the area that used to be covered by Petermann 2010-A and 2010-B will have on the glacier. These areas should ice over during winter and melt next spring. In any event, the glacier appears to be at the mercy of deep ocean currents and not the surface waters of the fjord. The front edge of the glacier probably extends 60 meters or more below the surface level. The warming of surface waters may slowly eat at the front edge, but will have little affect on the the water that comes into contact with the bottom of the glacier.

    The glacier is supposed to be some 600 meters thick at its grounding line and the fjord has a depth up to 1100 meters. By 20 kms from the grounding line, the thickness of the glacier is reduced to 200 meters. This melting is due to ocean currents melting the glacier from the bottom up (basal melting) and reaches a maximum rate of 25 meters per year about 10 kms from the grounding line. The melting by this ocean current appears to end by 30 kms from the grounding line, after which the glacier thins very gradually until it reaches the calving front. The reduction in thickness of the glacier after 30 kms appears to be based solely on the surface melt rate of approximately 1 meter per year. Based on this profile, the influx of heat from ocean currents would appear to override the impact caused by surface waters.

    If the glacier maintains this melting profile, it may not retreat much further than the existing fissure line and may advance after this calving event.

    In the radar images above, this fissure (which has been growing for several years) already extends across half of the glacier, and yet, the glacier has not calved. If the glacier can resist calving with a fissure this long, then the portion behind the fissure may last longer than anticipated. I guess if future fracture zones and fissures developed behind the existing fissure would there additional significant calving to cause retreat to the grounding line, but the thickness of this area may prevent this. If the grounding line of the glacier were to retreat due to melting by ocean currents, then the retreat may continue, otherwise, it is possible that the glacier will advance.

    Admittedly, any advance of the glacier back down the fjord will be slow as it only advances about 1 km per year.

    While there is some speculation that this rate may increase due to the calving which occurred in 2010, this may not be correct as it assumes that the portion of the glacier that calved was exerting "back pressure" on the glacier.

    The glacial tongue that calved was already afloat and much thinner than the portion of the glacier behind the new calving line. The front portion of the calving, what is now Peterman 2010-B, was not in contact with the sides of the fjord and probably offered little or no back pressure on the glacier. Based on the images previously posted and annotated at Petermann Ice Island Revisited, it appears that the remaining portion which calved, Petermann 2010-A, was not in solid contact with the walls of the fjord.

    The images also show that the portion of the glacier that remained behind the new calving front is not in solid contact with the walls of the fjord, particularly the eastern wall of the fjord, due to chatter from ice streams that enter from the sides. The pictures at Jason Box's blog from the 2009 expedition show the sides as unconsolidated. The side ice streams may be exerting more pressure on glacier flow than the floating areas of the glacier downstream of the side flows. If the portion that calved had no friction with the side walls of the fjord, how much "back pressure" could it have been causing?

    In reviewing the history of the glacier, Andreas Muenchow stated that: "We went back to 1876 to find all glacier positions that have ever been reported. From this analysis, we found that this indeed was the largest event that has been observed at Petermann, but that the trend of area lost by this glacier over the last 140 years is indistinguishable from zero."

    In contrast to this quote, Jason Box of the Byrd Polar research center has estimated the decline in thickness of the glacier in the fjord since 1865 at 885 feet. Even at this pace, the floating portion of the Petermann glacier may last for some time to come.

    Petermann Glacier’s Trimlines Indicate ~270 Meter [885 foot] Thickness Change Since Circa 1865.

    Source of numbers above is from a paper issued before the 2010 calving:

    Ocean circulation and properties in Petermann fjord, Grrenland by H. L. Johnson, A. Muenchow, K. K. Falkner, and H. Melling at:

    Will: thank you for all the input. 

    I appreciate the point about surface waters.  However, with the extra open water area and the frequent strong winds blowing down the fjord I would expect a greater mixing due to Ekman transport.  In addition, greater penetration of warm Atlantic and Pacific waters into the Arctic could be reflected in greater water temperature in the Nares Strait and hence Petemann Fjord.

    As for the under-ice melting mechanism: consider why the ice becomes tapered in length.  If the water penetrating under the ice causes melt then it loses heat with each advance under the ice.  Less heat produces less melt.  I would expect the greater mixing to carry ever more heat under ever less ice.

    The presence of Petermann Ice Island has reduced the amount of old ice being pressed into Petermann Fjord.  Last winter the old ice formed almost an ice shelf in the fjord estuary, and that ice took a long time to melt.

    Thick ice in Petermann Fjord.
    image source:

    Most of the ice in Petermann Fjord this winter will be new ice, as shown here.  My projection is that the ice will melt earlier in 2011 than it did this year.

    The large fissure extends perhaps 60% of the width of the overall width of the ice, allowing for the way that fissures develop and for the limited satellite image resolution.  The ice to seaward of the fissure is in a narrowing part of the fjord, so some of the forward pressure will be converted to lateral pressure.

    The ice island was calved this year once the sea ice had melted out from a substantial area of melange.  I suggest that the same thing will happen next year, but sooner.  Once the sea ice has melted away from the front of the glacier and from the melange in the 'chatter zone', the next strong wind will calve the ice back to the major fissure.

    I'm afraid that's all I have energy for today.  I'll try my best to come back soon with more discussion on this fascinating glacier.

    Patrick, thanks for replying.

    Glad to see you are better.

    Sorry to be belaboring this point, but the melting that occurs under the ice shelf at Petermann is not happening as described above and this may affect the conclusion of retreat back to the grounding line made above.

    This is not a suggestion that human induced warming is not occurring in the arctic (it is obvious that this is occurring), rather it is a suggestion that such warming may not occur in a fashion that permits the recent calving events at the Petermann glacier to be extrapolated in a linear fashion to make a prediction of the location of the future calving line of the glacier.


    The dynamic for under ice melting of the glacier described above of more heat at the front and less as the water travels further back, while intuitive and what I expected, appears to be different from the melting pattern observed at the Petermann glacier. The article clearly found a signature of the heat transport from Atlantic currents into Petermann fjord, but it is not clear how much this will increase the basal melting over the level that is already occurring.

    The Atlantic water does not appear to be losing heat as it advances from the front of the glacier to the grounding line. Instead, the heat transfer is occurring far back under the ice shelf, with maximum melting occurring at 10 kms from the grounding line (25 meters per year), with the transfer of heat from the ocean current diminishing toward the front as the glacier thins. Based on this fact pattern, warmer Atlantic waters will not thin the glacier front and thereby cause additional calving.

    The article explains this counter-intuitive result by stating that:

    "the presence of relatively low density, intruding winter mixed water beneath the ice shelf forces the rising plume of Glade-like, melt-influenced water to detach from the bottom of the ice shelf, and prevents melting from occurring higher in the water column. This suggests that oceanic influence on the thickness of the ice shelf is reduced when the base of the ice rises above the base of the ocean winter mixed layer at approximately 100m depth. Subsequent thinning of the ice shelf will be controlled by the surface energy balance on top of the ice..."

    This surface melt rate is only 1 meter per year.

    The article then raises the question:

    "Does the ice, then, thin to the minimum achievable by oceanic heat transfer long before reaching its terminus, and yet remain too thick to calve?"

    Based on the data in the article it is possible that retreat will not occur beyond ice thickness of 100 to 135 meters (I am not sure where this occurs, but the article found that bottom melting from ocean currents ceased about 30 kms from the grounding line). The ice is 200 meters thick at 20 km from the grounding line and 600 meters thick at the grounding line. It may be possible to maintain this profile even with the loss of the glacial tongue beyond 30 to 40 kms.


    The data does not support a reliance on insolation or the Ekman Effect for future calving. The article mentions Ekman circulation in section 4.2 in discussing geostrophic flows. It is possible that surface water can flow away from the glacier depending on wind directions. The article in this section noted a geostrophic flow out of the fjord. The article also noted that there is a cyclonic gyre at the surface at the entrance of the fjord

    An additional constraint on heating from insolation would be the mixing of the less dense fresh water melt from the glacier with the the salt water in the surface in the strait. Surface water is discussed in section 6 of the article.

    Another limiting factor on the contribution from insolation is that the time period for its impact would appear to be fairly brief as the article noted that:

    "Sea ice is also likely to be important. In most recent years there has been open water in the mouth of the fjord for only a couple of months, limiting the watermass transformation that can occur due to sea ice formation. The lid of fast ice present throughout much of the year will moderate the effects of windstress and air-sea heat exchange."

    The article directly addressed the additional heat input from insolation to the melting of the bottom of the glacier and concluded:

    "Current heavy sea ice conditions keep surface temperatures in the mouth of the fjord low throughout the year. Ice-free conditions in summer would allow surface temperatures to warm, although this direct effect of insolation is unlikely to extend deep enough (60m) to warm the water that is positioned to move under the ice shelf."


    The measurement period for the data in the arcticle is brief and it is not known what changes the recent calving will have on the ocean currents and melting of the bottom of the glacier from ocean currents. The authors of the article were well aware of the potential for the calving we have just witnessed and yet, they were not able to come to any conclusion concerning the future position of the calving front of the glacier.

    The article appears to suggest that it will not be insolation or future fracturing from tidal forces acting on the glacier that will cause such a retreat (behind the existing fissure), but rather an increase in basal melting over the 20 kms closest to the grounding line from "warmer incident Atlantic waters"; however, the authors state that further study "is required to provide a definitive answer to the question of what determines the melt rate and calving frequency/location."

    While I admire the boldness of a prediction of a retreat back to the grounding line, the existing data and the current state of the scientific understanding of the forces acting on the Petermann glacier are insufficient to support such a conclusion. In the absence of such understanding, and the focus of this web site on science, I would caution against making a prediction of such a retreat.

    One final caveat:

    Please note that even with the recent increase in warmth to the arctic and to the Nares Strait, the Petermann glacier advanced 4.5 kms down the fjord from 2003 to 2007 after a calving event in 2001. Nothing indicates that this ability to advance down the fjord after a calving event has ended.

    Petermann 2010-A may have struck Hans Island (tiny white dot to bottom left of red blob that is to the right of Franklin Island). This may slow, but should not stop 2010-A.

    Will & Patrick: Thanks a lot for your outstanding explanation behind what's going on regarding the Peterman glacier. I feel much more educated now!
    Will, your last comment regarding the development between 2003-2007 was highly fascinating, and I tend to support the wiew upon the significance about the global warming. This in itself is not enough to make the Peterman retreat, BUT the last 2-3 summers have proved much warmer than normal on the western part of Greenland. Last summer/autumn had seatemperature in the Baffin bay 6-8 degrees above normal, and as Patrick is pointing out, this must lead to an earlier icefree zone in front of the glaciertongue?
    But I am no Glaciologist, though I have been to classes and trips with Atle Nesje, but that is 15 years ago, and my education took another direction....

    Hope for more input from you both!

    Thanks for reading.

    Patrick is clearly correct that seasonal ice zones, including the area in front of the Petermann glacier, will show longer periods of open water as the heat content of the water and atmosphere increase. Areas that have not had open water in the last 3 to 4,000 years will have open water in the future.
    He is also correct that the loss of albedo creates more warming.

    Glacier behavior is not so simple, and perhaps all we are discussing is a question of timing.
    I would agree with him that some day in the future, if we do nothing, the Petermann grounding line will melt out, the current floating portion of the Petermann glacier will disappear, and a significant portion of the Greenland ice cap will be flushed down Petermann fjord into the sea. I just can't show or predict with certainty the date it will happen.

    I respect the work Patrick is doing here and Neven and others do at getting this information out.

    In August of 1991 a smaller calving of the Petermann glacier occurred with three pieces breaking off.

    The 2010 calving broke off much further back than the 1991 calving. The pre-calving front in 1991 appears to have been approximately 5 to 8 kms further down the fjord than the pre-calving front of the 2010 calving. There is an August 19, 1991 radar image that shows the Petermann glacier just before the calving that indicates the location of the calving line at:


    Have you or could you post the image of the 1991 calving in your next update?

    Will, you're REALLY into this!

    I guess there's a great difference between Peterman to glaciers like Nigardsbreen, that retreated fast when revealing a lake underneath it. The depth of this lake probably wasn't deep enough to make the glacier calf into it, thus retreating faster, but still?!

    If you're having any nice glacier sites to recommend, I would be thankful. I'm to busy to this blogging, but during the winter I have to catch up, if my wife "allow" me! Cheers!

    And Patrick, you just see to be OK!

    If Greenland glaciers are your thing try this 1995 publication:

    which has a view of Petermann from August 2, 1976 in figure 34 on page C57

    Or you might try here

    Petermann Ice Island 2010-B has now a beacon!

    You can see actual position of the buoy 47557 here:

    Petermann Ice Island 2010-A just passed Franklin island.

    The rifts that form on the northeast side of the Petermann Glacier are unusual for most glaciers but not for this glacier. These rifts are always signs of weakness that precondition a floating portion of a glacier to failure. In the case of many ice shelf settings because of low velocities such rifts can endure for a time before leading to failure. In recent years we have seen the nearest to the front large rifts last for two years before failure on Petermann Glacier. Petermann Glacier tongue loses little velocity from the grounding line because of limited lateral or basal shear. The result is limited acceleration or deceleration which tends to allow weaknesses to persist without large additional stresses to quickly enlarge them. The Petermann as Johnson and Muenchow well show, and Will points out melts considerably when the base of the glacier is below 200 m, but not when it is thinner, which it is in the last 30 km of its floating section. It is not evident that this will change. The melting of the ice tongue is primarily well back of the ice front. I do not see a compelling reason why the Petermann Glacier tongue retreat will accelerate next year. The balance of forces has not changed much. We do have the one exceptional rift which should fail next year or the year after.

    Petermann A in radar image of 25th:

    By the 27th Petermann A has drifted out of Kennedy Strait image below:

    Both A and B in Kane Basin image at same time on the 25th with a large unrelated ice island headed for Pim Island:

    Only A and unrelated piece, which is slipping by to the east of Pimm Island in image for 27th:

    Same time image for 27th of B heading into Baffin Bay:

    Where will they sail to next?

    In case you haven't seen this.....

    Hope you're feeling better?

    Petermann 2010-B had been headed southwest. Shortly after the radar image above for 16:43 on the the 27th, Petermann 2010-B reversed course and circled back north closer to Ellesmere Island than the path it took when it was heading southwest. It then headed north east and at the time of this writing it appeared to be headed due east. If there is a circular current here, it may turn and head south again, inside of its original track.

    The link below will show changes to the path that occur after this writing.

    The current radar image from very early on the 28th does not show the area for Petermann 2010-B :

    Hi Patrick,

    Just back from a month long trip to The Himalayas and Nepal, besides the beautiful nature the tops of the mountains look browner or less white than they did 23 years, my last time there. So suspect we do have an "arctic" problem there too?
    I can see we are having a relative high freezing rate in the arctic and earlier than expected, I speculate can it be because of the low contents of salt in the seawater in the area? Hoping you are feeling better now than a month ago!

    Regards Espen

    Petermann 2010-B has completed looping back on its original track and is currently headed west toward the south east corner of Ellesmere Island. It may turn northwest and enter Smith Bay. If it heads about 60 miles south, then it may enter Glacier Strait above Coburg Island. The 2008 Petermann Island drifted south in front of Coburg Island (National Wildlife Area), then reversed course and headed back north then went west where it entered Glacier Strait and became trapped in Jones Sound behind Coburg Island.

    The tracking lines for the 2008 Petermann Ice Island is on page 55 of 59 of a 2008 presentation which can be accessed at:

    Petermann 2010-B has completed its second loop.

    The 2008 ice island eventually got out of Jones Sound and continued its journey south along Baffin Island to Frobisher Bay. Tracking information and pictures of the 2008 Petermann ice island are at:;jsessionid=E1F55A3CC17283A...

    Headed North again.

    Now heading eastward for another loop around.

    Going nowhere fast.


    Has there been more calving at theann Glacier?

    Compare September 30 below:

    with a more recent image:


    What do you make of the big ice chunk that just went by the fron of Petermann fjord?

    Somehow it missed Joe Island.

    It was part of the ice pack in the Lincoln sea.

    Looks like that area is still breaking up:

    compared to September 30 image:

    and September 28th image which shows the big ice chunk:

    Hans Island splits large ice floe.

    Before it struck Hans it looked like this:

    Both Petermann ice islands in same image as the "B" piece continues to circle in a gyre.

    hi Will, I noticed that too, no wonder the islands up in that strait looks the way they do with all those collisions over the years. But I am more worried about the fact we dont hear anything form Patrick???

    I hope he is OK. Has he posted on Neven's open thread?

    I hope it is ok that I have been posting the links to these images. I am certain that you and others are looking at the same images.

    I've just spoken to Patrick. He's been ill, and decided to rest as his draft attempts at writing weren't up to par, and he deleted them again after re-reading. He is on meds, though complains they don't make him feel like a 6 year old, and will be back soon, hopefully not writing like a 6 year old - wink Thanks for the concern Aitch
    Good to hear. Best regards Espen

    Get well soon Patrick.

    Thank you all for your concern and for keeping this article up-to-date with links and observations.

    Will Crump: particular thanks for your excellent contributions, they are very thought-provoking.

    I concur with what you and Mauri Pelto have to say about retreat to the grounding line being unlikely in the very near future.  However, I'll stick with my prediction of a retreat to at least 50% of the ice tongue length as it was in 2009 by 2012.

    It is very frustrating to have little energy.  I like to reply to comments individually, but I am currently working on my October Arctic ice update and need to save energy for that.

    Thanks again, everybody.
    Good to hear from you Patrick and thanks to Will, Espen, Henry, and others for the updates on your health and this article. Hope to see you back in your writing form asap. Maybe some Butterscotch Schnapps would help, lol.

    To all arctic followers, be aware, we are in the final part of the race around the pole, the Norwegians are in the lead at moment, just 400 km (220 NM) of the coast of Iceland, so within a week or so we will have the result of this race, which was made possible not because of change in climate, but just sudden change of weather, if I am correct!
    Follow their journey here:

    Best Regards Espen

    Will. Yes. Ejected. It was waiting for A.

    Now reunited. Awwwwww.....
    (Big image, but you can't really see them at lower res. Just opposite the mouth of the big fjord in SE Ellesmere Island - Smith Bay?)

    October update preliminary:

    As we could be watching during this melting season 2010, we never saw that much rotten and fragmented ice in the arctic. But now its official:

    According to the National Snow and Ice Data Center:

    At the end of the summer 2010, under 15% of the ice remaining the Arctic was more than two years old, compared to 50 to 60% during the 1980s. There is virtually none of the oldest (at least five years old) ice remaining in the Arctic (less than 60,000 square kilometers [23,000 square miles] compared to 2 million square kilometers [722,000 square miles] during the 1980s).

    So my conclusion we are only a few seasons or maybe even only one season away from the total collapse of the arctic summer ice!
    This update will be continued by Patrick. Regards Espen

    I find it mildly amusing, the shift from what used to be considered 'Old Ice' in the polar regions The public in the main think in terms of it never having melted and often guesstimate its age to be i.r.o 20,000 years or something similar My brother in law used to work in UK's famous Smithfield meat market which was was subject to modernisation while he was there. The underground ice store, at Smithfield, which survived a 3 day fire in 1958, contained carcases of beef over 30 years old, frozen and undisturbed, as newer stock had been added on top, and was only discovered in the modernisations, so..... 5 year old is very young for polar ice .....and virtually none left! WOW,,,,,,,,and no major headline news, due to 'ice' still being visible Just goes to show, not all ice is created/remains equal, eh? ;-) Time to heed nature''s warnings mayhap? Aitch
    Hi Henry,

    Yes it is amazing that there are no reactions in the media about these facts. But that is how the media works unfortunately.

    Petermann´s Ice Island appeared on daily ice analysis map "Approaches for Resolute" issued by Canadian Ice Service.

    It is marked by egg symbol "A".

    Recent radar image of the Petermann ice islands:

    Image from RADARSAT-2 taken October 12th and released last week of Petermann ice islands A, B, C, D, and some other floes.

    Will: many thanks for all the links and updates.  Your contributions are greatly appreciated - as also everyone else's.

    Resized - 75% - image:

    Petermann Ice Island parts clustered.

    It appears that these giant icebergs are all affected similarly by currents which end up circulating or stalling in a relatively small area.
    A new image as of October 26th has been posted at:

    November 1, 2010 - - Surface area measurements of Petermann Ice Islands on October 26, 2010:

    PII-A = 72 km2
    PII-B = 86 km2
    PII-B-a = 28 km2
    PII-B-b = 12 km2

    On October 17, 2010, two Iridium beacons were deployed on PII-B with an additional one deployed on PII-B-a. These 3 beacons were deployed on the Petermann Ice Islands by ArcticNet researchers aboard the CCGS Amundsen in collaboration with the CIS. These beacons transmit their locations via the Iridium satellite network to receivers at the University of Manitoba.

    As of November 4th, one of the Petermann ice Islands is mid-way down the coast of Devon Island and closely following the coastline.

    NEWS: Climate Change October 21, 2010 - 6:42 am
    Mammoth ice islands menace Arctic wildlife, environment, ships
    Scientists plant more beacons to track path of ice islands

    Ice continues to be exported through Nares Strait

    Lincoln Sea on October 30, 2010

    appears to have more openings than it did on October 21, 2010

    Petermann Glacier as of October 21, 2010

    and October 20, 2010 (includes Lake Hazen)

    and October 16, 2010 (includes Lake Hazen)

    Continuing to follow the progress of the Petermann's fragment down the coast of Labrador, as I'm due to return soon to the Grand Banks for work on an oil rig.
    Does anyone have predictions for the likely flow directions form it's current location on the mid-Labrador coast just north of "Port Manvers Run".
    I'm (moderately) surprised that there hasn't been more mention of this in the news media (though I'm working up an information pack for a couple of journalists that I know). The Newfies seem to make a significant tourism thing of iceberg-watching, so I'd have expected them to pay attention to a big one like this coming in their direction. That's neglecting the potential for it to cause real havoc to the oil installations (not a minor industry locally itself).

    Does anyone have links for the beacons on the various smaller icebergs?

    What are the current sizes of the bergs?

    To partly answer my question of last night ...
    Gives me the AQUA/MODIS image for 2011/142 05/22/11 16:30 UTC (Rapture+22:30, I blame the volcano myself) ;
    What I think is the ice island (from the Buoy 47557 page) is in that image in a box approximately at X 2178, Y 1235, 28pix wide by 47pix high. (I've tried to get the box about the same area as the apparant ice island).
    28pix by 47 by 0.25km/pix is 6.75 by 11.75km, or

    Still chunky then.
    Now, can I find Hibernia et al on those pictures? Not a hope - they're in a fog bank.

    Just as a matter of interest - since I may be trying to fly tomorrow morning - Uh oh ... is that coming our way? Yep, it's coming our way.

    Update on May 27th imagery.
    The cloud cover has thinned enough to see the ice island again (well, it might be visible by other means ; anyone who knows how, let me know!), and repeating my previous process on the most recent image I get an area of 31x47 pixels, which more-or-less validates my previous estimate. They're either both wrong or both right (-ish).
    The ice island appears to have rotated by around 90/270 degrees compared to the last clear sighting - the transponder track would suggest that it's 270 degrees.

    The image I'm examining is MODIS/ AQUA crefl2_143.A2011147165000-2011147165500.250m.jpg, near the link of a few days ago. The satellite won't be passing over again until a few hours from now.

    I would prefer iceberg spotting rather than plainspotting, but I guess this is Hibernians nightmare come true?!
    My father was one of the "generous" norwegians to make the Hibernian project become a reality, after the french failed, back in the 90'ies. They are likely ready to send an army of tugboats towards the icebergs, but Petermann might be too much even for them?! Dynamite.....

    Working in the industry as a geologist, I have a slightly different view on what time period risks should be accounted over than most. A once-in-a-century storm is something that anyone would engineer to manage, but many wouldn't engineer for a once-in-a-millennium storm ; I would.
    The seabed of the Grand Banks is ploughed with many deep furrows - "tool marks" - some of which are deep enough and old enough to get mentioned in seismic reports. Bergs crossed the area in the past, ploughing deeply into the seabed ; bergs will cross the area in the future, ploughing deeply into the seabed. Claiming that Petermann's calves doesn't have the potential to do so in the very near future is unconvincing.
    Looking at issues like the design of wells for this sort of environment, I'd definitely have specified that sub-surface shutdown equipment be installed at a depth corresponding to rocks that predate the current ice age - about 5 million years, which would be several thousand feet below surface here. (That's the fail-safe equipment that wasn't installed on the Piper Alpha and killed 167 of my colleagues early in my career.)
    Whether the people who did the design work on Hibernia et al, I don't know ; I 'd certainly hope so. But regardless of that, someone should be keeping a very close eye on this, even if they're not shouting about it in public. Given weather conditions there and helicopter availability (limited by sea state, since the Flight 914 report earlier this year), it could credibly take several days to down man the installations. (That's deliberately leaving the lifeboats as a last-hour option ; always have something in reserve!) To firmly close in all the wells and vent and clean all the tankage in preparation for evacuation .. that is likely to take around a week with a full crew on board.
    I'm sure that the Canadians are doing the necessary close watching and have got the relevant plans off the shelf and are double-checking their relevance and how to achieve those plans. But I'm not hearing much about such planning and preparation. I suppose that may be to try to avoid upsetting nervous children (a.k.a. investors), but that leaves a worryingly ostrich-like silence. Actually, I know that some people in the business there are awake to the issue ; whether they're being listened to is another question.
    Could tug boats make a useful difference against something this size? I doubt it. Tugs are rated by bollard-pull, which directly relates to the size of their propellors and the power of the engines that drive them; if the wind and current forces on a berg exceed the bollard pull capabilities of the tugs arrayed against it, the berg is going to win. And the forces that wind and water can exert on a 6km+ stretch of many-metre-thick ice are going to be big. (That doesn't exclude tugs being able to change a berg's course, but the less the time available, the more the course changes have to be, and the earlier you have to have started). (Another complication is that there are multiple installations to avoid hitting ; really you don't want this thing to be anywhere near the whole region).
    Dynamite is likely to turn one problematic berg (or asteroid ; the problems are analogous) into several, and not change their courses. So you've now doubled the number of towing operations (of dubious success) that you need to carry out. It might be a rational choice in some circumstances, but I wouldn't start from there.
    Anyway, it seems that Loki and Thor were at a pre-Rapture party last Saturday, and came up with a delicious plan to torment the mortals. So now I'm nervously eyeing the dark cloud in the North sky. I'm sure Tolkein said it better.

    Article : "2 Greenland glaciers lose enough ice to fill Lake Erie"
    "The new study suggests that, in the last decade, Jakobshavn Isbrae has lost enough ice to equal 11 years' worth of normal snow accumulation, approximately 300 gigatons (300 billion tons) of ice."

    It looks as if Petermann I has groundes. Or is it common for bergs to stop along this coast?

    Hi Aidan,

    I can tell you're into this! But one aspect you haven't put into words is how DEEP these bergs are. My father told me that when working at the Hibernian project, many bergs showed up, but at a safe distance they got stuck, grounded, and if some of these big chunks of ice did happen to ground in the local fjords, well, then the summer those places were bound to be severe or more or less devestating for the local agriculture!

    Petermann have to go deep, and will possibly ground many times until reaching those latitudes!?

    My father did tell me that the tugboats were highly efficient for moving the bergs, with large nets, and automatic release safety in case the ice starts to roll, risky business, but given time, any berg are moveable....

    Hi Christoff,
    Seabed in the areas I've worked on (within sight of Hibernia, not that that says a lot ; these things can be seen from a long way off) is at around 100m below MSL, (we'll not worry about the difference between MSL and LAT, though it's important to be clear on this when you're planning things to less than a few metres). So using the rule of thumb that 90% of a berg is below sea level, then if the residual thickness is less than ~110m, the berg can get close enough to the big installations to make a pre-emptive evacuation and blow-down (shut in the wells, empty all the tanks and pipelines of flammable materials, "Brace! Brace! Brace! for impact!" as the pre-flight video says) an urgent consideration. The Wikipedia page for the Hibernia says 80m water depth ; Terra Nova doesn't give a depth (I should have it somewhere, but if I have to look out the paperwork, I'd have to assume that it's confidential data ; same for White Rose ; whatever).
    The Wikipedia page for Petermann refers to it's thickness "The tidewater glacier consists of a 70 km long and 15 km wide floating ice tongue whose thickness changes from about 600 m at its grounding line to about 30–80 m at its front." But what the thickness is after spending a year at sea ... who knows.

    This is a *very* important question. Well highlighted.

    So, presumably, someone in the monitoring people will be monitoring the HEIGHT of the berg very closely ; while it's above around (say) 12m, then it's not a cause for concern UNTIL it fragments again.

    Unfortunately, one of the things that I can think of that is highly likely to cause a berg to fragment is ... grounding. The tidal stresses around the hinge line (boundary between the seabed-supported parts of the berg and the buoyancy-supported parts of the berg) are going to cycle 4 times per day. That combined with melting is ... well I can't conceive how it's NOT going to encourage calving of things that float.


    I've received my flying orders. So this is going from purely academic to personal in the near future.

    No updates from the transponder for a day now. Something wrong, or just weather?

    Looks like it's moving again, made over a degree since it got free. Appears to have veered into shore again, which may indicate another "touch bottom" event.
    Can I find any decent bathymetry for this area? That would give some information about the thickness of the island.

    Arrived in Canada and (eventually) out to work on the Grand Banks. as anticipated, people are keeping a "watching brief" on the ice island, and it was confirmed almost as soon as I arrived that the transponder has, indeed, gone the way of all flesh. And of all electronics.
    My back of the envelope estimate is putting it at N 55.400951, E -57.282715. with a "position angle" (in approximately the sense the astronomers use the term) of 160.
    I think that it's rotating counter-clockwise, but I'm by no means sure of that.

    A very crude estimate gives about 50 days until it's in this area, but I believe the professional forecasters are putting the numbers a little lower. I'll talk to the rig's forecaster when I get settled into my shift pattern.

    Just a quick update. The island is still trundling slowly along the Labrador coast. According to the Canadian weather forecasters I talked with when last there, this suggests that the berg is going to end up grounded along the NL coast, and eventually break up and melt. In contrast, it's the bergs that head out into the Labrador Sea that travel considerably faster, get out into the Atlantic and cause trouble for general shipping.
    With the transponder dead, the effective tool for remote monitoring is satellite imagery. Which falls foul of the wonderful NL weather. But it can be seen often enough. As of yesterday (July 3rd) it was making progress from offshore from Makkovik towards Emily Harbour.

    Damn. Clicked the wrong link and un-subbed. Looks like I need to re-post to re-sub.
    What's the location? I was diving over the weekend and haven't looked for a couple of days.
    Hmmm, Newfoundland in the clear, but the coast north is under cloud ... get the 250m image ... which is murdering my processor ... It's visible in , and oriented to the west. But I can't see enough coastline to get a position. Does seem to be making progress though. Lets' see what it's up to tomorrow.

    Almost completely unrelated, I heard this poem on the radio a few months ago and had forgotten about it until I just found a copy laying around.
    (Just the first verse, because I'm not sure of it's copyright status ; but it was easy enough to find.)

    By Les Barker

    On a cold rainy night on a Liverpool quayside
    In the years before the Great War
    The world was in shock at the loss of Titanic
    So proud had they been days before.
    Relatives gathered for news of their loved ones,
    To read through the list of the dead,
    When into the throng came a sad-eyed Polar Bear,
    And to the clerk at the counter he said:


    Have you got any news of the iceberg?
    My family were on it you see,
    Have you got any news of the iceberg?
    They mean the whole world to me.

    Aidan: thanks for the comments and updates.

    Just for you, here is the giant's baby brother, just leaving the fjord after getting stuck in the sea ice.  My guess is it's getting out of harm's way before the next ice monster comes thundering down the fjord.  ;-)

    Well Patrick, you could think of it as getting out of the way of next year's TROUBLE, but I'd think of it as having heard that my friend Abigail is working on a drilling rig off Disko Island, and has decided to rush down the coast to meet her.
    I'm sure that she'll be delighted to meet the berg. [G]

    Just been catching up from my not-exactly-ice-bound job site (see photos on home page).
    After an extended sojourn on the coast near Makkovik, the berg has rounded the corner down the final leg of the Labrador coast. It seemed to do this pretty rapidly, between 19 July (when it was "rounding the corner" near Black Tickle (who comes up with these names?) and 29th July, when it was in the throat of (the sound between Newfoundland and Labrador, whose name escapes me at this moment). Near Belle Isle.
    It was still a little south of Belle Isle on the 5th August, and has been in the murk since.
    Last visible position (from my sources) was date 05/08/11 time 16:15:00 Lat. 51.53 long.-54.95 position angle 020.
    (That last one is the direction the "arrowhead" shape is pointing it ; I hope to be able to see it's rotation in the satellite photography, but I haven't seen it clearly in the data yet. It's probably irregular.)

    I'd expect that the NL press is talking about it again. But I've gtot to get back to work before my network connection dies again.

    (the sound between Newfoundland and Labrador, whose name escapes me at this moment). Near Belle Isle.

    Strait of Belle Isle, perhaps ?

    Many thanks for the update, Aiden.
    Sounds straight up to me!
    Don't worry, I don't intend to give up the day-job.

    does denmark or canada have sovereignty over the petermann ice island??? if u know be so kind to answear me

    does denmark or canada have sovereignty over the petermann ice island??? if u know be so kind to answear me

    Hi Christina-from-B,
    You know, I've never heard of anybody actually investigating the legal status of ice islands and icebergs. Since they are all ephemeral (after a while, they disappear again. Permanently.), though of different lifetimes (from several years to a matter of hours for the smallest of "bergy bits"). They are all a continuum, so what applies to one size applies to all others, unless someone draws a metaphorical "line in the sand" for some reason.
    What would be the reason for claiming sovereignty over such an ephemeral island? Well, firstly if you've claimed it (say, for the Principality of "Sealand", to pile ridiculousness upon ridiculousness), then obviously you've got responsibility for any damage that it causes. So, if Sealand had asserted sovereignty over Petermann II, and it had then ground over the Hibernia oil fields ... then the bailiffs would have been hammering on the heilpad of Sealand with a multi-billion lawsuit for damages. (On the up side, Sealand would have effectively acquired recognition by dint of having been sued.)
    What would be the benefits of claiming sovereignty over an ice island? Well, I guess that you'd have the mineral rights. To a lot of ice. Fresh water. (And a small amount of random contained rock.). Now, I could see that the fresh water has a significant value - tow it to the Persian Gulf and see if you can undercut the price of water from their desalination plants.
    But you could acquire the same property rights by going to the Danish (Greenland) government and just buying the island while it's still part of Greenland. Then assemble your fleet of several hundred ocean-going tugs ($30,000/day on the spot market, but you might get them cheaper by booking them several years in advance), attach them to the iceberg (you'll need to hire Canadians for this - I've not heard of anyone else with significant practical experience at moving icebergs), break the iceberg away from the source glacier, and tow it away to the Gulf. I leave the question of minimising the melting during transit, and of marketing the water at the target market as exercises for yourself. It's not physically impossible, but it's not likely to have me tearing money out of my mattress to invest in.
    So, who has sovereignty? I simply don't know, and I doubt that the question has been seriously discussed. The icebergs are (and have been recognised as) a hazard to shipping in the North Atlantic, and much of Canada's, Greenland's, and a significant chunk of America's material trade travels on these routes. Which is ample reason for them to shoulder the costs of the monitoring of icebergs. Beyond that, I'm not sure that the question really matters.

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    In case nobody has noticed, the Petermann glacier has claved again, though only 40-odd
    And the MODIS imagery : (about 30% from the left edge, 80% of the way down the image.