Author Topic: Nares Strait - when will ice bridge break in 2018 (Read 11117 times)

Tor Bejnar · « **on:** May 05, 2018, 01:15:56 AM »

Identifying the date ice across Kane Basin near its northern end moves (showing cracks) will be the goal. (Ice bridges further north in Nares Strait may remain in place. The first or current southern ice edge may break long before ice moves in the northern part of Kane Basin.)

This inspired me:

Quote from: bbr2314 on May 04, 2018, 06:26:25 AM

It looks like the impact of "no Fram" due to warmth will imminently entail the re-opening of Nares for export. Massive cracking extending towards it as of yesterday. Probably won't take much to break the arch and start early transport of MYI toward Baffin.
...

Some may want to know some history:

Quote from: oren on May 12, 2017, 01:55:08 PM

Did some quick research about approx. breakup times, southern "arch" in Kane Basin unless noted otherwise:
2007 - No arches formed.
2008 - June 10th(?)
2009 - No southern arch. Northern arch broke around June 30th.
2010 - July 10th
2011 - July 5th.
2012 - June 30th.
2013 - July 10th.
2014 - June 20th.
2015 - July 5th.
2016 - June 30th
2017 - No southern arch. Northern arch broke around May 10th.
...

We can all win if it breaks this next week or so, as votes can be changed!

oren · « **Reply #1 on:** May 05, 2018, 07:46:13 AM »

Nice poll. I saw bbr's message and thought to myself how it always seems breakup is imminent, but then it takes ages to actually happen.

johnm33 · « **Reply #2 on:** May 05, 2018, 11:22:33 AM »

It'd be interesting to know how much the an early forming of the arch affects it's durability. Late may.

uniquorn · « **Reply #3 on:** May 05, 2018, 12:53:47 PM »

The arch looks pretty solid for the next few days. ECMWF forecast is no higher than -10C till may14th.

uniquorn · « **Reply #4 on:** May 06, 2018, 09:44:38 PM »

polarview may5

Tor Bejnar · « **Reply #5 on:** May 10, 2018, 07:57:28 PM »

Looking back, on April 28, a piece of the (lower) Kane Basin arch broke off. Image from Worldview. I didn't see any evidence of breakage since then.

oren · « **Reply #6 on:** May 11, 2018, 02:48:35 AM »

Bear in mind there are two lines of defense this year. The current visible arch, and the original arch which is somewhat to the north of it. It shows clearly on uniquorn's animation from May 5th. So in my conservative view, breakage of the arch should mean the original one, as potentially the current arch could go well before anything else breaks up.

uniquorn · « **Reply #7 on:** May 29, 2018, 12:33:46 PM »

It's difficult to tell whether this is a small break or wind blown slush from the south.

oren · « **Reply #8 on:** May 29, 2018, 01:55:01 PM »

There was a definite but tiny break in the south corner a few days ago.

bairgon · « **Reply #9 on:** May 29, 2018, 08:49:21 PM »

Yes, I've been watching it slowly being eaten away, with a lot of melt on ice further down the channel.

Looking at the other end shows massive breaks like the picture below from yesterday (the cracks have closed up a bit today). This shows that the normal bridge of thicker ice that normally forms from the top of Greenland is non-existent this year.

bairgon · « **Reply #10 on:** May 31, 2018, 08:36:53 AM »

Signs of breakup further up the Strait.

Adam Ash · « **Reply #11 on:** May 31, 2018, 01:23:50 PM »

Once gets the impression that a decent ice breaker could trundle through mush that a undiminished speed. (Tho a bit difficult to say from here!)

uniquorn · « **Reply #12 on:** June 02, 2018, 09:07:01 PM »

Another nibble

oren · « **Reply #13 on:** June 02, 2018, 11:34:41 PM »

Remember that the pieces falling off belong to the extension, while the original arch is still there (shown clearly in the June 2nd image). I wouldn't be totally surprised to see the ice fall back to the original arch line, and then stop for a while.

be cause · « **Reply #14 on:** June 03, 2018, 03:14:53 AM »

the arch may not have broken but a lot of ice is on the move to the north . the ice looks thinner or has lost it's snow cover since early May . It looks as if the water is too warm to sustain the ice . My bet would be the arch is gone in a few days but another week or two before the channel is fully operational .. b.c.

Niall Dollard · « **Reply #15 on:** June 05, 2018, 01:12:57 AM »

The pressure on the Nares ice bridge is coming on. A crack has appeared in the Kane Basin to the north east of the main bridge.

Tor Bejnar · « **Reply #16 on:** June 05, 2018, 03:09:05 AM »

Quote from: Tor Bejnar on May 05, 2018, 01:15:56 AM

Identifying the date ice across Kane Basin near its northern end moves (showing cracks) will be the goal. (Ice bridges further north in Nares Strait may remain in place. The first or current southern ice edge may break long before ice moves in the northern part of Kane Basin.)
...

Niall has shown the ice near its northern end of Kane Basin has moved, and I see a thin 'longitudinal' crack through that area (and a larger one across the 'middle' of Kane Basin). So the June 1 - 10 voters have won: congratulations! (And we are all losers due to its early breakage.)

(I'm not sure this counts for Oren's list, though. We should document the lower Kane Basin bridge breaking here, I think.)

oren · « **Reply #17 on:** June 05, 2018, 03:28:55 AM »

Quote from: Tor Bejnar on June 05, 2018, 03:09:05 AM

Quote from: Tor Bejnar on May 05, 2018, 01:15:56 AM
Identifying the date ice across Kane Basin near its northern end moves (showing cracks) will be the goal. (Ice bridges further north in Nares Strait may remain in place. The first or current southern ice edge may break long before ice moves in the northern part of Kane Basin.)
...

Niall has shown the ice near its northern end of Kane Basin has moved, and I see a thin 'longitudinal' crack through that area (and a larger one across the 'middle' of Kane Basin). So the June 1 - 10 voters have won: congratulations! (And we are all losers due to its early breakage.)

(I'm not sure this counts for Oren's list, though. We should document the lower Kane Basin bridge breaking here, I think.)

It does not... often we see the northern part begin to churn while the southern arch still holds.
In general I think it is important for posterity to cross-post the animations and images in this thread to the general Nares thread, which can later serve as an excellent historical resource. I keep meaning to do that but find myself procrastinating.

Tor Bejnar · « **Reply #18 on:** June 05, 2018, 05:34:49 AM »

Oren,
I slightly mis-wrote... I actually thought the upper Kane movement (meeting this thread's criteria) did not meet the 'lower Kane bridge breaking' that your gathered data show. So, I concur with your "It does not". I intended to also write that "When the lower bridge breaks, it should be noted here." But I'll accept the Nares Thread may be a better place to document such events.

oren · « **Reply #19 on:** June 05, 2018, 07:03:40 AM »

No worries, I did understand your meaning. In any case, I like these annual Nares threads, and breakage should ideally be updated both here and in the main "repository" thread.

oren · « **Reply #20 on:** July 02, 2018, 12:31:49 AM »

I know competition rules were set up differently, but I consider the Nares southern arch of 2018 to have broken on June 30th.
The good news: using my own definition, my prediction managed to (randomly) hit the mark.

be cause · « **Reply #21 on:** July 02, 2018, 01:11:21 AM »

funny .. I missed this poll entirely . Interesting that this year joins 2016 and 2012 in opening on June 30th . Will it ever close again ? The upcoming storms look like causing a few busy days and the thick ice north of Greenland once again has a choice of stage exits . b.c.

Tor Bejnar · « **Reply #22 on:** July 02, 2018, 03:02:46 AM »

If I had thought out potential Kane Basin ice breakage processes, I would have designed the poll saying ice through the length of Kane Basin needed to move and cracks show (not just near the north end). If that had been the poll, June 30 would be the date. So, would-be congrats to the 6 brave souls who voted for late June. (I missed 'this' poll by a day.)

Niall Dollard · « **Reply #23 on:** July 02, 2018, 01:29:46 PM »

Quote from: oren on July 02, 2018, 12:31:49 AM

I know competition rules were set up differently, but I consider the Nares southern arch of 2018 to have broken on June 30th.
The good news: using my own definition, my prediction managed to (randomly) hit the mark.

Mmmm. Going by these sentinel images it still looked pretty solid on the 30-06-18 compared to the significant breakup evident on the 01-07-18 image.

That would n't be because my prediction was first week in July or anything

oren · « **Reply #24 on:** July 02, 2018, 01:44:32 PM »

Actually you are correct. I thought the bottom image was the one from June 30th.

Ned W · « **Reply #25 on:** July 02, 2018, 02:30:17 PM »

Looks to me like it was starting to break up on 30 June and is clearly broken up on 1 July.

Of course the exact time of breakup falls between the 30th and 1st, i.e. on the boundary between poll bins. I guess this is why we have overlapping bins now on the ice extent polls.

I didn't vote, so as an objective observer, I'd say that anyone who voted either 21-30 June or 1-10 July is ... half-way correct. Nobody wins!

Ned W · « **Reply #26 on:** July 02, 2018, 03:09:48 PM »

Here's a Sentinel-2 image time series from 29 June to 1 July:

29 June:

30 June:

1 July:

and here are enlargements of the southeast corner, at 20 meter resolution (this is Sentinel-2 bands 12, 8A, and 7 displayed as red, green, and blue, respectively):

29 June:

30 June:

1 July:

oren · « **Reply #27 on:** July 02, 2018, 05:19:05 PM »

I have a post of long term data about Narea breakup, so I'm more interested in that context.
I will dig it up and update it over at the main Nares thread.

uniquorn · « **Reply #28 on:** July 02, 2018, 09:53:07 PM »

Nice analysis everyone. What was the final verdict?

oren · « **Reply #29 on:** July 02, 2018, 09:54:55 PM »

My criterion says July 1st, the date when it was clearly gone.

Tor Bejnar · « **Reply #30 on:** July 03, 2018, 05:17:41 AM »

Did you look at Ned W's June 30 image?
See Sentinel-hub for June 30 (not the best configuration)

Quote from: oren on July 02, 2018, 09:54:55 PM

My criterion says July 1st, the date when it was clearly gone.

RikW · « **Reply #31 on:** July 03, 2018, 01:22:59 PM »

I'd say June 30th.

In Ned W pictures, it is still a smooth edge on the 29th and on the 30th it is broken

Niall Dollard · « **Reply #32 on:** July 03, 2018, 02:39:33 PM »

Three more slightly wider angle sentinel views.

June 29 : Two N-S cracks appear. Rightmost crack wider than the left. A large chunk breaks off the end.

June 30 : Some more smaller cracks appear at the SE section. Bear in mind that there is some high cloud in this image obscuring the large crack in the NE section of the image (underneath where the date stamp is.

July 1st : Widespread disintegration.

Ned W · « **Reply #33 on:** July 03, 2018, 04:12:44 PM »

Very nice, Niall.

That first image (29 June) shows one of the annoying things about the Sentinel-hub playground -- the image is stitched together from several different orbit tracks and during the interval between them the large ice plate at the southwestern edge of the ice bridge moved. So it appears (incorrectly) to have broken along a line which is not the actual break line. Here's a side-by-side of Sentinel vs Landsat on the same day:

It'd be nice if they had a way of turning off the mosaicking and showing only a single orbit track's worth of imagery at a time. Then you could actually track the movement of the ice on a sub-daily timescale. (Maybe there is a way to do that and I just haven't noticed it?)

I can get around this by downloading the actual raw Sentinel images, but it'd be nice if there were a way to see this online.

News:

Poll

When will the Kane Basin icebridge (arch) break in 2018

Author Topic: Nares Strait - when will ice bridge break in 2018 (Read 11117 times)

johnm33

Ned W

Ned W

Ned W