Nares Strait Flushing Poll

[Tor Bejnar]

Every year after the Nares Strait ice bridge(s) break*, it takes a while for the ice to flush out.  Once the ice gets going though, it can zip through.
Several years ago, Moira Dunbar published the attached table.

According to an internet calculator:
.83 m/sec  = 72 km/day
.59 m/sec = 51 km/day
.24 m/sec = 21 km/day

Nares Strait is just over 500 km long, so ice 'never' travels the distance in less than a week.

This poll will remain open until July 27.
_____
* - No ice bridge formed during the winter of 2006-7.

[Tor Bejnar]

My abilities to predict the future are decidedly horrible.  Therefore I expect to be the only person to vote 'late August'.   

[Neven]

Maybe it would be fun if you are going to follow a particular floe.   

[plinius]

given the temperatures in the NW passage region - would it also be possible that the Strait opens, but the Lincoln sea ice never reaches Baffin before late october?

[magnamentis]

fun post of the day   

of course this remains a real possibility, that it will melt before reaching the other side

[Tor Bejnar]

Attached is a screen shot from DMI's Kennedy - Sentinel-1 on 2016-07-06.  I have colored a "blue egg" and a "red apple" that are close enough to the margin between the Lincoln Sea and Nares Strait.  I'll follow this pair.  (also attached is a non-colorized image.)  The larger neighboring floes will probably break during their journey, but their pieces count too.  As a floe can get destroyed, we might want to consider this a relay race, and transfer the baton to whatever floe was just behind (if the pieces are too small to trace), even to a floe that clearly was waiting in the Strait all winter (after all, the tiny pieces will continue travelling south).

[Neven]

Okay, cool! Given the current forecasts I think it will take until the end of August for the apple and the egg to make it to Baffin Bay. Unless they melt out first, as it's going to be sunny there. 

[oren]

Took the first bin on a hunch that Kane Basin will flush in a few days, and this will give enough time for the rest of the Strait to follow through and allow the first Lincolns to reach Baffin Bay at the earlier date.

[Alistair]

I have also taken the first option as it is pretty broken all the way through and now that the bridge has crumbled the exodus should start about ... now.

[Jim Hunt]

The answer might depend on exactly where you draw the northern boundary of Baffin Bay. Ice Mass Balance Buoy 2013C got flushed through Nares, and then spent several weeks exploring Lancaster Sound before finally reaching Baffin Bay proper:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2013-imbs/#2013C

[Tor Bejnar]

Better to set the precise goal now then later!  The attached Nares Flush Finish Line goes from Cape Alexander, Greenland to Gale Point, Ellesmere Island. 

[TerryM]

Keep in mind that a floe can circle in the Hall Gyre for at least 3 cycles. Large chunks seem to prefer an outside track there as I recall.
I'll still opt for the shortest time slot.
Terry

[Jim Hunt]

The apple and egg are on the move.

I cannot help but wonder at this early stage whether they will still be intact and trackable as they near the finish line!

[A-Team]

Things are in motion as we speak. The animation, which needs a click to start, uses Aqua, Terra, and Suomo images in succession for the 8th and 9th of July (which is only partly in, and there only for Aqua). There is quite a bit of material from the Lincoln Sea being drawn in.

I'll replace the animation later in the day on the Nares forum when all 3 are in for the 9th. The frames are not equally spaced in time, in fact it is hard to put a time stamp on them given how they can be built from multiple passes.

[Tor Bejnar]

Okay, cool! Given the current forecasts I think it will take until the end of August for the apple and the egg to make it to Baffin Bay. Unless they melt out first, as it's going to be sunny there. 

Anybody who buys this 'argument' of Neven's should probably vote in the >Oct 11 bin.

Edit:  no votes in that bin yet?  Good try, Neven, in attempting to lure the good folks on this forum to that extreme position!  Of course, I failed at my attempt to keep late August all to myself.   

[Jim Hunt]

The latest Sentinel installment:

[A-Team]

The Lincoln Sea action is shown below through July 9th. Aqua, Terra, Suomo, Aqua, Terra, Suomo. We are lucky to have a couple of days of clear weather.

[A-Team]

Flushing continues through the 10th ... needs a click to animate. It runs at 100 ms per frame with a slight pause on the 10th. The slower animation is at a less favorable scale and runs slower.

Petermann Glacier has little to do with blocking Nares (and vice versa) as the glacier moves forward at only 3m per day towards its 10000 m wide mouth. The melange in front of the floating ice shelf is thin brackish FYI and has not yet melted out or broken up.

[Tor Bejnar]

Thanks, others, for your animations, etc. that show the big picture.

Attached a screen shot from July 9 showing the 'apple' catching up (some) to the 'blueberry'. The blueberry's north edge looks like it might break off or something (e.g., maybe just an old scar is showing). [Showcased floes are near the top of the image.  Petermann Fjord is [edit: NOT] at the bottom [it's Newman Bay].]

[Jim Hunt]

Sentinel from the 10th

[Tor Bejnar]

I've added color to Jim's image, approximating the floes that will identify the first Lincoln Sea ice to reach Baffin Bay this year:  the blue egg [why do I keep thinking "blueberry"?] (without its top, which may or may not be still connected), the apple (that might have an attached northern extension) and a yellow Johnny-come-lately (or banana - it's yellow) that was on the edge of the strait on 7-7-16 but with less distinct boundaries then.

[Tor Bejnar]

Obstruction:  there may be delays.  Big floe is stuck on Joe Island, just south of the Petermann Fjord mouth.  Will it break?  How long will it hold? (attached screenshot from Sentinel image from yesterday's DMI Kennedy folder.)  Today's NOAA AVHRR image (same DMI Kennedy folder) shows the blockage continuing.

To see if this causes votes to change:  currently, the five voting bins have 21, 9, 1, 1 and 0 votes.

[crandles]

Obstruction:  there may be delays.  Big floe is stuck on Joe Island, just south of the Petermann Fjord mouth.  Will it break?  How long will it hold?

Yes and not long.
https://lance.modaps.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r03c03.2016193.terra.250m

[Lawrence Martin]

"Obstruction:  there may be delays."

Obstruction appears to be over.

[Jim Hunt]

The blockage breaking via Sentinel:

[Tor Bejnar]

One blockage go-ith and another blockage come-ith!  The new one is in Smith Sound/southern Kane Basin.  This one won't slow down the named little floes unless it stays put for a while. (attached screen shot from Worldview)

[Lawrence Martin]

 
@Tor Bejnar  "One blockage go-ith and another blockage come-ith!"

That blockage  go-ith too...

[Tor Bejnar]

Boy, my delaying tactics aren't working very well.
I wonder what I'll come up with next?

[Shared Humanity]

If memory serves me well, once ice starts moving quickly south, few large flows are able to block the flow. They usually fracture under the stress applied by ice backing up behind it. The exception would be if we have a very thick, large, multiyear slab of ice but these are more difficult to come by.

[Tor Bejnar]

Forward progress:
First image is from Polar View on July 13 and shows Petermann Fjord's mouth on the lower left and most of Hall Basin. 
Enlargement is from near the upper right corner of that image and shows, to the best of my abilities (and my discernment of what went where these past couple of days), the blue egg (aka blueberry), apple and banana. [Edit: file name was mis-written "2012..." ]

Current votes in the 5 bins: 23, 10, 1, 1, 0.

[Iceismylife]

the other half of the blockage looks to be stuck on an island.

[Espen]

Be prepared for the Nares Express 2016:

[Tor Bejnar]

A little progress, especially for the banana.  Screen shot from July 15 Polar View.  The line is 82ºN.

[Tor Bejnar]

I might as well quote myself:

Obstruction:  there may be delays.  Big floe is stuck on Joe Island, just south of the Petermann Fjord mouth.  Will it break?  How long will it hold? ...

To see if this causes votes to change:  currently, the five voting bins have 21, 9, 1, 1 and 0 votes.

Voting bins now have 24,10,1,1,0.  The previous blockage apparently didn't last long enough to change minds.
Image from today's Polar View.  Today's blockage isn't complete, but appears to be effective.  Plus, another large floe may come along to plug the gap.

Further north (but not part of the linked image), the blue egg cum blueberry is pouting on the Canadian shore (and basically not moving) because I cannot decide what to call it.  The banana is slipping right along.

[Tor Bejnar]

Once again the blockage breaks.  This time, however, the breaking may not have cleared much of the blockage.  From today's Polar View:

[current bins: 25,10,1,1,0]

[Tor Bejnar]

From July 26 and July 28 Polar View images, I see the large floe that was near the Lincoln Sea is now past Franklin Island (26th) and Crozier Island (28th).  I've lost track of the marker floes, but they were behind this large floe.

I see the final vote tally is 26,11,1,1,0, so nobody appears to have changed their votes before the closing on the 27th.  Unless someone can show the progress of the 'banana' (that I suspect is ahead of the 'apple' and way ahead of the blueberry/egg), I think I'll have to say that when the first small floe after the 'green-centered big fellow' (yes, crudely painted) passes the finish line, I'll deem the race over.  Two weeks for the ice to get through Kane Basin, plus or minus.

Edit:  about 300 km to go, and from the chart at the top, an average sort of speed will take about 12 days.

[Paddy]

This year it's looking like there may not be a massive amount blocking the strait, but also not a great deal of pressure pushing ice down it, given the low concentration north of the strait.

[Tor Bejnar]

Screen shot from July 31 Polar View shows the 'big fellow' just north of Kane Basin.  The crossed lines are 80^oN and 68^oW.  The Greenland shore shows.

[Tor Bejnar]

given the temperatures in the NW passage region - would it also be possible that the Strait opens, but the Lincoln sea ice never reaches Baffin before late october?

The screen shot from the July 31 Worldview (with 'big fellow' colorized) shows not much ice in Nares Strait.  Is it all going to melt before reaching Baffin Bay?

[Tor Bejnar]

The 'big fellow' is languishing off Cape Madison, according to today's Polar View image.   (Screen shot below)  No progress in 3 days...

[ghoti]

So did it all melt out before reaching Baffin Bay? Looks very blue in the strait and I don't know how to spot the targets...

[Tor Bejnar]

I lost the original three targets, but settled on a 'big fellow' that remains just north of Kane Basin that I believe was in northern Nares Strait all winter (and, by the way, appears to be melting in place now). 

When I have some time, I want to see if any of the smaller floes closer to the Canadian side of the Strait are passing by (I'm going to guess they are.)  If true, I'll try to pick yet another target floe to follow.

A year or two ago I followed a floe from the Lincoln Sea to Baffin Bay, but I did so later in the season and the ice flowed quickly to very fast.  I vaguely recall it taking about 15 days for the entire trip.  I didn't realize how challenging it would be now.

[Tor Bejnar]

So, one of the 'do or die' dates has passed.  Did any ice that wintered in the Lincoln Sea pass into Baffin Bay before August 11?  I'm fairly certain the answer is "No."  This answer, however, is not as definitive as I'd like it to be.

on DMI's Kane Basin TERRA images, I traced a small floe that crossed the finish line on August 10 back to near a Canadian bay in Kane Basin (so not Lincoln ice).  Another small floe that was near the finish line on the 10th was traced back to southern Kane Basin on the Greenland side - this was lost under the clouds from August 1-6.

Using the Sentinel images, I traced a couple of floes that were in southern  Kane Basin (on the Greenland side) on August 10 to a mass of ice that overwintered in Kane Basin.  Other (August 10) southern Kane Basin floes appear to have been in northern Kane Basin on July 26, and well south of the 'big fellow' that I'm pretty sure was in Nares Strait all winter.

Plinius wrote on July 7th, "given the temperatures in the NW passage region - would it also be possible that the Strait opens, but the Lincoln sea ice never reaches Baffin before late october?"  Now, was that a premonition?

[Tor Bejnar]

Looking at DMI Kane Basin Sentinel images, a couple floes in Kane Basin that have been there for 2 weeks are still in Kane Basin (and these wintered over in Nares Strait someplace).  Although they were in more northern area a fortnight ago, they haven't passed south of 79ºN, and are not heading anywhere in particular (certainly not southward - see screen print from Windyty showing winds from the south in Smith Sound). 

Smaller bits of ice may have exited the Strait, but heaven knows where they came from.

The Windyty forecast shows mostly south winds, and sometimes blowing strongly. 

[Tor Bejnar]

The HYCOM model predicts some 5m thick sea ice will fill Nares Strait over the next several days (see Nares Strait thread for more on this.)

Across Nares Strait, winds are forecast to be strongly from the south tomorrow:
https://www.windyty.com/?2016-08-28-18,80.510,-65.237,5

So no Linclon Sea/Arctic Ocean ice export this week, but some thick ice may become available to make the entire trip soon.

[abbottisgone]

fun post of the day   

of course this remains a real possibility, that it will melt before reaching the other side

Do you only do one a day? All my posts are fun!

(Sometimes Neven tells me to slow down,.. and we all know I got a holiday over July but now I just have a more bespoken kind of fun.)

[budmantis]

Do you only do one a day? All my posts are fun!

[/quote]

They may be fun for you AIG, but not necessarily for the rest of us.

[Tor Bejnar]

I haven't looked for a while (largely thanks to Hurricane Hermine), but DMI's 12-September-2016 Kane Basin Sentinel-1 image (screen print below) shows a (probable) Lincoln Sea ice floe (circled in green) passing the finish line (along with some little bits and pieces).  The 2nd screen print is from Polar View on 11-September-2016 shows more detail.  (This finish line is approximate.)

[Cate]

Toggling between 14 and 16 Sept (clear skies) on Explorer, it looks to me as if there is still a lot of ice moving and thinning out up there. I am looking in particular at the entrance to the strait from the Lincoln Sea, where the ice is coming round the corner of Ellesmere.

When would you all expect it to slow down and freeze up?

[Tor Bejnar]

Nares Strait is often (always? in recent years) open at least into December (but I don't have the statistics).  In 2006-07, it never closed.  I understand that in other years no effective bridge formed, too.  Neven, in 2013, recommended The Broken Bridges of Nares for those who want to learn some history of Nares ice bridges.