2011 Nares Strait Animation

Now that the formidable ice plug in Smith Channel has finally broken up (see this blog post from a few days ago) the rest of the ice in Nares Strait gets a chance to start moving.

The coming days a high pressure system is forecast to roam the area, meaning 1) high temperatures and insolation that will further fragment the ice, and 2) clear skies that should deliver nice, clear MODIS images of the event. So the coming weeks I will update this animation that shows the whole of Nares Strait.

As always I advise to focus on one part of the animation, instead of trying to take it all in at once.

Update June 20th: Added today's image. Looks like the current has reversed!

Update June 21st: Added today's image. Current is still flowing from Baffin towards Lincoln, but there's a bit more fracturing around Franklin Island and in Kane Basin.

Update June 27th: Added today's image. The current has re-reversed!

Update June 29th: Some more ice breaking up at the entrance of Kane Basin.

Update July 1st: Added yesterday's image (day 181). Things are cracking up.

Update July 2nd: Added yesterday's image (day 182). Things are on the move!

Update July 3rd: Added yesterday's image (day 183). Except for the fast ice between Petermann Glacier and the Lincoln Sea, everything is moving.

Update July 4th: Added today's image (day 185). Even the fast ice between Petermann Glacier and the Lincoln Sea is moving now.

Update July 5th: Added today's image (day 186). Ladies and gentlemen, we have transport.

Update July 7th: Added today's image (day 188) and deleted a few others so that the animation doesn't get too big. Transport is still going, and fast.

Update July 9th: Added today's image (day 190). A lot of wind from the east apparently. Check out the blooms.

Comments

[idunno]

Hi Neven,

I think there is also a strong possibility that this year we may see extra export routes open up, through the Canadian Archipelago.

No certainty yet, and no likelihood of anything happening for a month or so, but it may be one to try to keep one of your numerous eyes on.

The other thing that strikes me, in the section you've animated here, and elsewhere throughout the CA and along the coasts of Greenland, is how sparse the snow and ice cover on land is.

A recent scientific paper detailed the contribution to sea level rise from melting glaciers in the CA. Looking at recent satellite images, this does not seem likely to last long. There is precious little snow or ice left on land.

The animation also leaves another question begging - does anybody know if the triangular "island" which is in the centre of the frame is in fact an island?

I believe that the scientific community have now decided that Greenland is not in fact a mini-continent, but actually an archipelago composed of three main islands, thousands of tiny little ones, all covered with a mile or so of ice...

As the ice retreats, we may soon start to see the outlines of more and more little islets, separated by small passages which will allow for the export of more Arctic sea ice...

Finally, on Day 169, I think that the section just behind the main break is already cracked, and another piece , about half as big, will be gone in a few days.

[Neven]

idunno, I did an animation on transport of ice through the CA last year in August. I'll definitely get to this once things start to move.

Finally, on Day 169, I think that the section just behind the main break is already cracked, and another piece , about half as big, will be gone in a few days.

I agree. Like I said in the previous Nares blog post - and going out on a limb, I admit - I believe it will take 2 weeks at the most for all of the ice in Nares Strait to be on the move.

But I thought the ice plug would be gone much sooner as well, so we'll see.

[FrankD]

idunno,

See (Wikipedia for wase, not authority): http://en.wikipedia.org/wiki/File:Topographic_map_of_Greenland_bedrock.jpg

The triangular area you refer to is a peninsula. However, its connections to the rest of Greenland are quite low, but I don't think a 7 metre sea level rise stemming from the complete collapse of the GIS would sever its connections. It will probably be an island in a thousand years or so when the EAIS falls into the Southern Ocean...

[idunno]

Hi FrankD,

I'm surprised at the Wikipedia entry. I have definitely seen other maps, which show the central sub-sealevel basin connected to the surrounding seas.

See for example:

http://www.cejournal.net/?p=4225

I suspect that the jury may still be out on bits of this...

[FrankD]

Hi idunno,

Yeah, there does seem to be some disagreement - but I'm not sure of the source of Konrad Steffen's data (the source of your link), so I can't comment on it.

The Wikipedia map is based on the best paper I can find (although 10 years old now): Bamber et al: http://www.cpom.org/research/jlb-ag.pdf

NSIDC still use a derivative of this map on more recent articles on bedrock in Antartica and Greenland.

[HenkL]

At 12Z today Alert (near the Robeson Channel) measured +12.4°C. At the Greenland north coast Cape Morris Jesup had +5,6°C at the same time.

[Arcticio]

Managed it to make a radar zoom of Nares Strait:

http://www.arctic.io/zoom/QAlT

Looks rotten.

[Paolo]

test

[Paolo]

2009/2010/2011
It is remarkable the differences for the fast ice north of Ellesmere Island (bottom right of pictures; the last refuge, ice with the north of Greenland, for the multiyear)
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2009168.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2010168.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011168.terra

[Paolo]

Big rip in East Siberian and begin melt near coast (top right of picture)
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r05c04.2011170.terra

Very rapid and big breaking in the Amundsen Gulf (top left)
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011167.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011168.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011169.terra
and for the picture of south of Amundsen Gulf
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r05c02.2011169.terra
and breaking in progress in the Barrow Strait (bottom)
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011166.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011168.terra
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r04c02.2011169.terra

[Paolo]

And to end melt lakes on the Greenland Ice Sheet (but 250 is better :-) )
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r02c02.2011169.terra

[Paolo]

Sorry, in my first post the right text is "north of Queen Elizabeth Island” and not “north of Ellesmere” as i write, and in the last post “but 250m picture is better” is more clear

[Neven]

Wow, Arcticio. That's impressive! How do you do that? Amazing...

Great collection of images, Paolo. I was just preparing an animation of the NWP and combined just those three images you posted above (for 2009, 2010 and 2011).

[Paolo]

New break in the Nares Strait
http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r03c02.2011170.terra

[Neven]

Thanks, Paolo. Day 170 has been added to the animation.

[Daniel Bailey]

@ Idunno

This image shows the Greenland rock morphology under the ice:

[Source]

Additionally, this image shows a topographic view of the Greenland bedrock:

[Source]

Apologies, Neven, for breaking your frames. The resizing commands do not appear to work here.

[Neven]

No problem, Daniel. One of them is turning, so we see it just fine. ;-)

The html tags for size indeed don't work here. I was hoping this would improve or could be controlled when upgrading to a paid version, but alas.

Anyway, just click on the image to see the full version, people.

[Daniel Bailey]

Thanks for the clarification, Neven.

If anyone wants the syntax for posting expandable thumbnails, as I attempted to do here, it can be found here:
http://www.skepticalscience.com/comments_policy.shtml#htmltips

[Andrew Xnn]

Paint.net is a useful program for resizing images. Less than 350 pixels wide seems to fit.

[Ucf Aeroengineer]

Hi Everyone.. I'm a total amateur at the sea ice thing so I'm learning as much as I can. I have one question about the greenland ice sheet: Has anyone done any modeling regarding it melting and the continental rebound that will occur? Those below sea-level areas in the center will almost have some interesting secondary effects. Granted, this will take a longer time-scale but I'm just curious if anyone has explored it.

[Artful Dodger]

Nice graphic, Yooper... Let's see what happens to Greenland with 50m Sea level rise: (click the image for the full-size version)

As you can see, the interior of Greenland will be open to the Sea in at least 3 places: in the North-East, North-West, and at Disko Bay.

This is the legacy we are leaving to humans of the far future.

[Peter Ellis]

Hmm, not really convinced. There'd be substantial isostatic rebound - the only reason the interior of Greenland is bowl-shaped is because it's got a mile and a half of ice sitting on it.

[Artful Dodger]

Perhaps in the long term, Peter. Wikipee says "Due to the extreme viscosity of the mantle, it will take many thousands of years for the land to reach an equilibrium level". However Sea level rise will happen on a scale of hundreds of years. If all land ice melts, sea level rise is potentially 270 m... which of course weights the interior of Greenland once-more, slowing rebound.

So it's a race. If we make irreversible changes to the climate with GHG emissions, we lose.

[Neven]

I've updated the animation. The current seems to have reversed. My prediction was based on the current flowing from Lincoln to Baffin, not the other way around. Interesting, nonetheless. :-)

[Peter Ellis]

Lodger: melting Greenland might be of the order of hundreds of years. Melting the complete Antarctic ice cap (i.e. your 50+ metre rise) takes thousands of years under all existing models.

I have no idea where you get 270m from - the maximum possible sea level rise from melting every ice cap and glacier on the planet is widely known of the order of 70-80m.

[Neven]

Feet instead of meters?

[Daniel Bailey]

270 feet or so is the accepted value of SLR associated with all of the fixed land ice melting. It would take the loss of the GIS, WAIS and part of the perimeter of the EAIS to get to 50 meters SLR. Plus about a millennia.

But as Dodger says, that can happen far more quickly than isostatic rebound (given the unburdening of much of the long-depressed crust/basement rocks, some rebound might still be measurable after a hundred thousand years or more in some areas). And some areas, like southern Britain, will sink...

[Christoffer Ladstein]

In Northern Sweden, along Bottenviken, the yearly landrise due to isostasi, still is 0,9 cm, more than 11000 years after the 3 km thick icesheet melted away, so I have to agree with Daniel, that THIS concern is not exactly a worry for the next generations.
As a curiosity I may mention that in the seventeenth century, they worried about a WATER-level decrease, and Anders Celsius therefore took the initiative to make marks in the rock along the coast, and thereupon later understood the mechanism of landrise.
Though it wasn't until the Scotsman Thomas Jamiesson in 1865 connected it to the Iceage they had "discovered" some decades earlier, they were able to fully understand it....This theory was fully accepted in 1890, after closer inspection of older sealevels, by Gerard De Geer.

I guess we have left the Nares thread now, Neven, sorry for this minor side track!

[Kevin McKinney]

Well, I for one appreciate it, Christoffer.

In fact, I'm taking notes. . .

[Kevin McKinney]

I should mention that Lake Superior's north shore show rates of rebound up to .53 cm/yr.

There's a paper about the differential rates of rebound around the Lake, and how the relevant datum needs to be adjusted to best balance the needs of hydropower, navigation, and so forth.

[Kevin McKinney]

Just reviewed the CT graphs for today.

The Archipelago's decline was a real jaw-dropper. I actually said "Wow" out loud.

Guess it goes along with those temps Lord Soth mentioned, but still impressive to see.

It augurs well for any Passage-takers this season. Anything special planned, or did last season's records take the lustre off of it as an adventure?

[Daniel Bailey]

@ Kevin

If you have a copy of that paper, could you send it my way?

Thanks!

[Lord Soth]

A 60 year record fell in Alert today. Got up to 14 Celsius, and broke the old record by two degrees. Not bad for not even being summer yet.

They are getting better weather on the northern tip of Ellsmere Island, than several places in Maritime Canada, lately.

[Kevin McKinney]

Sure, Daniel. It's Lee and Southam, 1994--a bit old, but interesting nonetheless.

Available here:

http://tinyurl.com/LakeSuperiorIsostaticPaper

[Daniel Bailey]

Thanks, Kevin!

[Artful Dodger]

Hi folks,

There is a nice ( 1-page ;^) paper from a presentation to the European Geosciences Union meeting last year. Nielsen et al. (2010) A Study of Glacial Isostatic Adjustment in Greenland says:

"The ice loading histories used for this study are derived from the ICE-5G model (Peltier, 2004) and the thermomechanical ice flow model SICOPOLIS (Greve, 1997)...

We find that the GIA signal from neither of the ice loading histories agrees with the GPS derived uplift rate, which highlights the need for further studies in this region in order to better constrain the ice loading histories as well as present and future sea level change is this region."

So "No Proof, No Case?" BAU 'til she blows? :^)

The actual problem for Humans in all this is Increased Vulcanism, as magma moves along rebounding mantle plates. It's possible that the best-case outcome is that the interior of Greenland floods, limiting crustal rebound.

Admittedly, this is a potential problem for the far-future from a Human perspective... but it's another in the litany of troubles which will be our legacy.

Ya think Global warming is hard to adapt to?... try putting this Genie back in the bottle! I can hear the faint chorus already: "IT'S WAS THE SONS..."

Cheers!

[Neven]

I had overlooked this heuristic forecast for ice conditions in the Lincoln Sea and Nares Strait by Gudmandsen.

Ice bridges or ice arches are common in Nares Strait. They generally form during the winter, blocking the transport of sea ice from the Lincoln Sea into Baffin Bay. Gudmandsen notes that this year the ice bridge formed at the end of February and exceptionally low temperatures in the following three months strengthened the bridge/arch and also increased the ice thickness in the Lincoln Sea. Gudmandsen predicts an early July break-up of the ice in southern Nares Strait, and break-up of the consolidated ice to the north (Hall Basin and Robeson Channel) two weeks later.

The more detailed forecast by Gudmandsen is here (PDF).

[Twemoran]

Is it possible that (relatively) hot water is being ejected from the northern end of Nares Strait causing the melt pattern now visible north of Greenland?
The high pressure system over Greenland could be forcing waters into the ever restricting Nares Straight which then jets it into the Arctic Basin.

[Neven]

Welcome, Twemoran. I think it's the current that is pushing the ice into the Lincoln Sea and creates a patch of open water.

If the current would be that warm to induce strong melting, it would melt the ice in Nares Strait first.

[Twemoran]

Thanks Neven. I've been following your blog since Jan - best on the web -
I suppose what I'm trying to understand is the reversal of the current in the strait - I know that in the great lakes a steep air pressure gradient from one end to the other can create a large difference in water surface elevations, hence flow from the high to the low pressure area.
If air pressures were higher over Baffin Bay, and lower north of Greenland a large amount of water might be transported under the ice through Nares adding to the melt in the north
The system seems to have changed today so it's probably moot.

[Neven]

I think you're when you say the reversal of the current is due to sea level pressure systems. In fact, understanding how the Arctic sea ice reacts to the distribution and position of high and low pressure areas, is key in making sense of what's happening (which is why I miss the PIPS ice displacement maps so much).

But I don't how much the temperature of that water is influencing the ice floes in the Lincoln Sea. Is it that much warmer than the water that is there?

[Artful Dodger]

In other words...

The truth is this: What we are doing is functionally insane. If we do not change this pattern, we will condemn our children and all future generations to struggle with ecological curses for several millennia to come.

-- Al Gore in Rolling Stone, “Climate of Denial: Can science and the truth withstand the merchants of poison?” June 22, 2001.

[Twemoran]

Yea - PIPS was wonderful

No idea of water temp beneath Lincoln Sea ice, but assume ice free waters would be warmer to some degree ;) I suppose volume would be the determining factor.

[Daniel Bailey]

Neven, Twemoran may be onto something. On a hunch, I checked out the Environment Canada page on the Nares Strait. There they document the breakup of the Nares Arch as well as confirming that normal surface water flow is from North to South.

Seeking an answer to the subsurface flow question, I checked out MUNCHOW et al 2011 (draft): "Ocean Warming of Nares Strait Bottom Waters off NW Greenland 2003-09", which analyzes subsurface flows within the Nares Strait. The evidence collected therein shows that warming Atlantic subsurface waters entering the Lincoln Sea have pushed over the 300 meter deep sill at the northern entrance to the Nares Strait and made their way south, warming the subsurface waters there and also impacting the Petermann Glacier, the polynas and the ice arches.

So the increased warming of the subsurface waters may help drive bottom melt by thinning the mixing layer underneath the ice (in the Lincoln Sea), but also contribute to the development of ice arches in the Nares.

At least that's my first-read of the paper.

[Werther]

Exciting new points of view on Nares Strait and Lincoln Sea. I followed Lodger (December ’10, ‘look out for transport north of Greenland to Fram Strait’) and Davidson (February ’11,’can’t remember ever seeing cracking up that far in the direction of Ellesmere’) up to counting floes myself lately. I like how you explore the possible drivers of that change over there.
For the record, Neven, as you asked for a count on my area using MODIS 2009 and 2010, I’ve done a brief comparison. First, day 163 2011 was very bright, whereas both 2009/10 had lots of clouds obstructing a good view for several days. Just superficial, I would say 2010 wasn’t much better than 2011. The striking difference is the pattern of the leads (resp. NNW-SSE / W-E) and a hunch of initial cracking of formerly unified floes in 163/2010. The remaining floes on Lincoln Sea today make an impression of settling dispersal between broad, persisting leads of rubble.
As for the subsurface temps of the ocean waters, I’m pretty sure that is the driving factor here. Very cold low atmosphere temps won’t drive ice growth on the floes as the thickness goes over 2,5 m. And those temps didn’t even fix the leads. Yes, they fixed Nares Strait, but underneath warming went on. I think that isn’t driven by surface flow, but upwelling. For two weeks, the ice in front of Peterman Glacier has become ever more blue and along Franklin Island it cracked without any relation to movement on the icebridges.
The SST's are interesting to watch, but I wonder what the 'eddies' on top of the warmer, more saline deep water are doing.

[Neven]

In that case I stand corrected. Gladly, as I love counterintuitive stuff. Great intuition, Twemoran1

And thanks for comparing, Werther! You can always contact me if you have some interesting CAD images etc. I still remember the one you sent me at the end of last melting season. That was quite a stunner.

[Werther]

The recount; settling dispersal...

[logicman]

Don't forget the tides!

Tides flow from each end of Nares Strait and meet in the middle - about 10 feet range if memory serves. That alone would be enough to cause the ice to be quite fractured in the region of Franklin Island.

The area of Lincoln Sea adjacent to Nares Strait is the site of the Lincoln Polynya. When the ice arch forms solidly in Lincoln Sea, the whole of Nares Strait can be virtually ice free.

Water above the freezing point of sea water has long been a regular feature from north Baffin Bay through to Lincoln Sea, with much annual variability of ice cover.

The area is worth watching daily now. Watch especially as the ice melts in Petermann Fjord. There is an ice island about 25km2 left over from last year in the mouth of the fjord. When it starts moving I expect Petermann Glacier to start calving again, big time.

[Twemoran]

Thanks guys - Pressures seems to have equalized with the stronger negative AO eliminating the differential. Weak anti-cyclonic winds may still push ice northward, but the current (bearing in mind tidal forces) should again be flowing to the south.
Any thoughts on whether the floes Werther is studying are headed out through Fram or Nares?

Where is PIPS when we need him.

If Petermann does it again at least the public may take notice.

[Neven]

Any thoughts on whether the floes Werther is studying are headed out through Fram or Nares?

On this map of the International Arctic Buoy Programme, most buoys seem to be moving towards Fram (in the last 60 days), even buoy 83724, just off the coast of Greenland, which had been stuck there for quite a while.

[Twemoran]

Little off topic but the product of the last major calving event has been tracked far down the Labrador coast.

http://www.cbc.ca/news/canada/newfoundland-labrador/story/2011/06/23/nl-ice-labrador-623.html

Almost enough to make me wish I was back that way:)

[Neven]

If my eyes do not deceive me the patch of open water where Nares Strait ends and the Lincoln Sea begins, has become smaller again. This could mean that the wind/current has reversed again. But it's cloudy unfortunately, so no updated animation.

[Twemoran]

Right now the winds are generally north in Nares Strait due to the pressure gradient between the High over Greenland and the (relative) Low south of Ellesmere.

Lincoln Sea has (slightly) higher barometric pressure than western Baffin Bay so I would expect the Nares current to be again flowing southward but with thin surface ice blowing to the north under all those clouds.

Woops - pressure gradients have shifted slightly while I was writing this, but we will see where it's at as soon as the clouds disperse.

[Neven]

Twemoran, if I may ask: What tools do you use to keep an eye on SLP?

[Twemoran]

Neven, I've been using DMI,University of Cologne and WeatherUnderground for data from specific sights. BTW that huge low west of Ellesmere showing on the University of Cologne map may stir things up a bit, I think I counted 9 isobars!

[HenkL]

The low west of Ellesmere on the map of Cologne is fake. Actually there is high pressure NW of the Canadian Archipelago.
Recent observations can be obtained using my (free) program WXDecoder:
http://software.wxgr.nl/WXDecoder.htm

It decodes SYNOP, METAR, SHIP, BUOY etc. The user interface of the program is Dutch only.
Most observations can be found at the 'main' hours 00, 06, 12 and 18Z, available about half an hour later.

[Neven]

Lucky me, I'm Dutch. :-)

Now this meteorological/software n00b needs to find a way to make sense of it all.

Bedankt, Henk!

[Twemoran]

HenkL - I'm getting 994hPa at MADIS
lat: 78.07
lon: -116.60

Do you think their sensor is acting up? - It is far lower than Aulvic or Resolute, although these are far to the south.

[HenkL]

The 994 hPa from that buoy must be an error. Nearby Canadian stations have SLP above 1020 hPa with calm northerly winds.

Good luck, Neven. There is a helpfile with the program (press F1).

[HenkL]

The analysis charts from the Canadian Weatheroffice also doesn't show a Low west of Ellesmere, on the contrary:
http://www.weatheroffice.gc.ca/analysis/index_e.html

[Twemoran]

Seems that the MASIS buoy was the source of the problem - and that HenkL picked up on it right away.
Good Stuff!!

[Neven]

Another piece of the ice in Kane Basin has broken off. I'll update the animation later today.

I don't think my forecast of all ice on the move within two weeks (July 2nd) is going to come about, perhaps due to that reversing of the wind/current.

[Twemoran]

Don't fold your hand yet. Gale force winds are possible in that area and it looks like a bridge too far at this point.

Besides - three days is a long time.

[Lord Soth]

The Ice Bridge has finally fractured totally.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r03c02.2011181.terra.250m

[Neven]

I was about to remark the same. It looks a bit like domino at this point in Nares Strait. Cracks everywhere, even in the blue ice near Petermann. How much longer for ice transport from the Lincoln Sea to get underway?

Some major breaking of landfast ice near the New Siberian Islands as well, and in McClure Strait. I'll update the animations later tonight.

[Neven]

Don't fold your hand yet.

Thanks for helping me hang in there, Twemoran. ;-)

Everything is moving now in Nares Strait, so I wasn't far off when I wrote on June 19th:

I think everything from Smith Channel (where the ice plug has finally conceded) to Kennedy Channel (where Franklin Island is) is going to fragment rather quickly, perhaps in a week or 10 days.

The rest of the frozen mass between Kennedy Channel and the Lincoln Sea - which looks a bit stronger - will probably follow soon too. I give it two weeks, tops, for things to be on the move in the whole of the strait. I base this on the forecast of a high pressure system in the area, meaning high temperatures and clear skies, combined with a strong current (I don't know if it is).

[Lord Soth]

Well this is three weeks ahead of what the Canadian Ice Service has predicted.

[Tor Bejnar]

Icebergs near the Petermann Glacier have moved southwestward 10-20 miles in a day (depending on the iceberg) while bergs leaving Kane Basin have moved southwestward only 5-10 miles. But there doesn't seem to be any blockage. (From looking at July 4, 5 and 6 sets of Kane and Kennedy "sheets" at http://ocean.dmi.dk/arctic/modis.uk.php)

[Neven]

Welcome, Tor.

It's a bit crowded at the southern exit of Nares, but otherwise things are very much on the move. Today's image was a bit cloudy, so maybe better luck tomorrow.

[Twemoran]

The ice remaining in Kane Basin seems to be fracturing perilously close to the calving front of the Humboldt Glacier.
Should we expect anything spectacular this season?

[Daniel Bailey]

Twemoran, the Humboldt is an example of a Marine-terminating in Shallow Water glacier; as such the greatest opportunities for acceleration in mass loss is due to basal melt.

Glaciologist Mauri Pelto and I collaborated on these Skeptical Science posts on Greenland:

1. Greenland Ice Sheet outlet glaciers ice loss: an overview
2. Zebras? In Greenland? Really?

The latter article has the Humboldt classified as a Type 4:Marine-terminating in Shallow Water glacier.

Petermann could offer up some short term news interest, but the big danger lurks from Zachariae Glacier: that is the one to keep a weather eye on.

[Twemoran]

Thanks Daniel - I'd read your 'Zebras?' post previously, but lost it in my bookmarks. Good Stuff!!
Any thoughts on why the Humboldt has not produced a terminal morain? Is it possible that one exists, but has not been detected as of yet?

[Daniel Bailey]

Twemoran

The first link I listed previously has a graphic showing the Humboldt in cross-sectional profile. The lack of confining topography and the terminus ending in the sea means that any terminal moraine (if any exist) would have to be below the current sea level further offshore.

It is likely flow rates were never high enough to produce a sizable moraine for Humboldt, though significant debris fields from rafted ice exist all around Greenland and throughout much of the North Atlantic.

In any event, terminal moraines are more important for land-terminating glaciers such as Mittivakkat (part of this article) in Southern Greenland or alpine-type glaciers.

[Werther]

On a detailed level, Twemoran’s attention for Humboldt Glacier made me shift 600 km to the SW on the same MODIS image while working in CAD.
Guess what... Summer does do it’s workout there, too. The snowline creeps up by the day. Intermittently, melt lakes 1-2 km² show up or drain. LBNL a small calving event again (I’m going to be expert on this, though I’d like some verification) on the Humboldt bulge, 4 km² down in the time lapse day 177 – 190.

[Twemoran]

Daniel - Werther
Thanks for the info. I had been speculating on the possibility that the calving front of Humboldt was resting on a permeable morain like deposit that might be eroding when Nares Strait went into high gear causing a strong gyre in the Kane Basin.
Yesterdays 33hPA pressure gradient between Lincoln Sea and Northern Baffin Bay produced just such conditions.
In April 2005, with a differential of just 16 hPa gale force winds destroyed a camp at Lafayette Bay at the southern end of Kennedy Channel. The winds were constrained by the canyon walls with clear, calm conditions elsewhere.

http://www-hce.coas.oregonstate.edu/~rms/ms/NS_Climat_revised.pdf

I believe that the flow rate - even the direction of flow though Nares Strait may be susceptible to these same forces just as occurs within the Great Lakes.

With Nares flowing southward at a relatively high velocity, the gyre in southern Kane Basin may erode some of the face of Humboldt especially any areas that are presently afloat.

[Twemoran]

I don't thing Petermann is due this season - BUT - A large circular piece of flow (multi-year or possibly part of an erstwhile ice shelf), has been bumping along the northern coast of Greenland. It entered Nares Strait on the 9th, got caught on the outside of a gyre at Petermann Fiord, and slammed into the first year ice protecting Petermann Glacier today.
It hit with enough force to crumple the leading edge of the new ice, close the crack that had opened, and possibly has disturbed the tongue of the glacier.
Today's Aqua and Terra images show it hitting and rebounding, and images from the 9th show it entering Nares Strait.
Again I don't believe Petermann has had a long enough gestation period to calve again this season but -

[Daniel Bailey]

Twemoran, the Petermann (and other ice streams) calves due to thinning of the glacial floating tongues. Some studies suggest that warm water penetration under the floating tongue has increased, thinning the tongue even more than before.

It is very conceivable that the impact you describe could propagate far enough upglacier to reach a point of weakness, triggering a calving event at some point.

Nice detective work.