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When will the ice bridge in Kane Basin collapse

before end of April 2020
4 (17.4%)
May 2020
5 (21.7%)
June 2020
10 (43.5%)
July 2020
3 (13%)
August 2020
0 (0%)
September 2020
0 (0%)
after September or not at all in 2020
1 (4.3%)

Total Members Voted: 21

Voting closed: April 01, 2020, 07:51:55 PM

Author Topic: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)  (Read 2117 times)

Tor Bejnar

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Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« on: March 16, 2020, 06:51:55 PM »
A discussion in the Melting Thread suggested this poll:
(since Nares Strait is not delivering nearly enough at this time of year

This would be zero so far to be pricise. The NS is frozen over and there is a stable southern arch at the moment.

I'm guessing here, but NS export could be extremely low this year. The temperatures in the area have been lower than average during the winter and the arch might break late in the year or not break at all.
To 'count', ice in Kane Basin must be mobilized, shown by upstream cracks (at least) into Kennedy Channel past red line (see translucent red line on attached map and image - map is from here, March 16 Sentinel image is from DMI).
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Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #1 on: March 16, 2020, 06:53:40 PM »
For historical reference:
I'll try Wdmn. :)

For what i know (and this is little) there are two possible situations: A southern or a northern arch. The obvious difference is, that when the arch is in the south, there is no export of sea ice from Lincoln sea. A northern arch can also mean no export but only if the arch stays stable.

A southern arch is more likely.

The arch normally breaks down in summer, not early spring.

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.
2018 - June 30th.
...
No bridge formed in 2018-19, so there was nothing to break in 2019.
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Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #2 on: March 16, 2020, 06:58:33 PM »
There is about 200 km between the current ice bridge and where ice must be broken to.  Somebody managed to vote before me!  (Good on ya'!)
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blumenkraft

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #3 on: March 16, 2020, 07:05:29 PM »
Voted June. Because i always vote pessimistic in votes.

I can't believe i didn't think about making it a poll. I'm glad though you posted it, Tor. Because you provided an amazing context to the initial post which i wouldn't have done. You rock, mate. Thanks a lot. :D

oren

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #4 on: March 17, 2020, 03:41:32 AM »
Nares breakup, my favorite subject...
In statistical reality this is a vote between June and July (the poll has a too-low resolution). Given that the definition demands breakup far above the arch, I voted July, also considering that the arch is is a stable location and that it's been a cold year in Nares.
A possible surprise would be for this to happen in the second half of July. Of course, early breakup (first half of June, May) is also possible, but IMHO improbable. Northern arches have more volatile dates.

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #5 on: March 17, 2020, 05:08:42 AM »
Current view

Juan C. García

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #6 on: March 17, 2020, 05:56:23 AM »
6 June, 4 July...

I will go for June (even that 4 June are on June 30th  :P ).
« Last Edit: March 17, 2020, 06:01:47 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

johnm33

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #7 on: March 17, 2020, 09:10:05 AM »
May 25th , can't remember when I last guessed right.

blumenkraft

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #8 on: March 17, 2020, 10:30:47 AM »
First Sentinel 2 pictures are coming in and they already deliver a surprise.

There is a polynya in the northern Kane Basin.


GIF at link.

Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #9 on: March 17, 2020, 01:38:04 PM »
There's an early polynya there every year (that there is a southern bridge).  E.g.:
The little polynya at the northern end of Kane Basin just off Cape Jackson is back.  It forms every year long before the ice bridge collapses.  Attached is a piece of the latest DMI Terra image showing just the northern end of Kane Basin with Cape Jackson and the polynya circled.
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blumenkraft

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #10 on: March 17, 2020, 02:35:56 PM »
Every year, eh? Good to know.

Seems bigger this year?

tybeedave

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #11 on: March 20, 2020, 12:13:27 AM »
my 1st poll, i picked July for the same reasons as oren said upthread *before i read his post*
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tybeedave

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #12 on: March 29, 2020, 10:24:27 AM »
i changed my vote....it is collapsing now i think :(

 td
thinking good thoughts, doing good deeds, enjoying good results - steve

be cause

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #13 on: April 21, 2020, 01:51:09 PM »
that's funny .. I had settled on June 30th .. then I saw Oren's little list .. June 29th it is then .. :) .. b.c.

ps .. liked I had 420 likes on 4.20 .. power to the puffers ..  ;D
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 =  ' if only we could have seen it coming ' ...

Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #14 on: May 16, 2020, 04:31:13 PM »
Just to not 'lose' this thread before its time, I'll report that Gerontocrat posted a fine radar image showing Kane Basin looking just peachy (if you want the ice to hold) in the Nares Strait thread.
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Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #15 on: June 25, 2020, 05:05:33 PM »
B_ published a GIF in the Nares Thread (Reply #2353) that 'confounds' the premise stated in this poll (except that it is happening mid-month).  That GIF shows ice in Kennedy Channel somewhat 'mobilized' and there are cracks and polynya in the Kane/Kennedy boundary, but Kane Basin ice is still pretty stable, and the cracks in the boundary area don't extend to (or from) mid-Kane Basin. 

I rather doubt this state of affairs will remain unchanged for 6 more days, but we'll be watching.  What fun!  (The 3 'July' voters still have a chance.)

I agree with B_ that when the bridge breaks, the entire Nares Strait ice cover will start flowing.
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blumenkraft

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #16 on: June 25, 2020, 05:33:40 PM »
Premise, shlemise!

Let's just take the subject line as the premise. ;)

be cause

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #17 on: June 25, 2020, 11:59:59 PM »
June 29th is getting closer .. as is our grand opening . Then ten days later , the garlic Press .. :) b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 =  ' if only we could have seen it coming ' ...

be cause

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #18 on: June 27, 2020, 08:28:33 PM »
there is a report of movement the length of the strait on the melt thread , but I'm not so sure , little movement at the N end beyond the new crack .. but it does seem only hours away ..
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 =  ' if only we could have seen it coming ' ...

Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #19 on: July 01, 2020, 11:10:00 PM »
The Nares Strait ice bridge has not collapsed as of July 1, according to DMI Sentinel-1 images.  There is lots of evidence ice is breaking up in Hall Basin (near Petermann Fjord) and the ice is deforming plasticaly in upper parts of Kane Basin and in the Strait just above it.  The Kane Basin ice arch may be moving, itself, a little, and I see cracks, but "it ain't obviously broke".

Congratulations to the three who voted for July!  (Unless the bridge stays where it is until August.)
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oren

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #20 on: July 01, 2020, 11:21:27 PM »
I did vote for July based on the stable arch and cold winter, but given the slow peeling in early June I really thought it was gonna blow. In late June it was a goner but the wind did not cooperate to give it the coup the grace. So funnily enough, my original vote turned out to be correct after all. Even a stopped clock and all that.

Tor Bejnar

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #21 on: July 01, 2020, 11:31:26 PM »
Here's the messy bridge.  June 29 and July 1 images.
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Niall Dollard

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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #22 on: July 01, 2020, 11:45:01 PM »
Thanks Tor for organising this.  :)

Yeah it's a bit wobbly now.

Reminds me of the Tacoma Narrows Bridge collapse !!


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Re: Poll: Nares Strait (Kane Basin) Bridge Collapse (2020)
« Reply #23 on: July 02, 2020, 03:10:35 AM »
Old Tacoma narrows bridge otherwise known to locals as Galloping Gertie.