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idunno

Hi Neven,

Slightly off-topic:

I'd just noticed within the Regional Search Outlooks that, due to low air temps over winter, there is a prediction from some reputable source that the Nares ice bridge will survive until mid-July - much later than in some previous years.

Lord Soth

It may have been cold this winter in the Canadian Arctic, however the summer tempertures do get quite warm, with 24 hour sunlight over much of the islands in the archipelago.

Practically all the ice in the North West Passage routes, is weak first year ice, and will melt out.

The ice in the Queen Elizabeth Island is five meters thick and 4-5 years old, and if it does break up, it will be very late summer, so it should not float south and block the passage, before it has time to open.

I will eat my shorts, if the main route (McClure Strait, Viscount-Milville-Lancaster Sound) does not open this year.

On another note, according to Cyrosphere Today, sea ice are is at record low for this date, and sea ice extent appears to be very close to a tie for a record low for this date.

Misfratz.wordpress.com
the ice on the Pacific/Canadian-Alaskan side of the Arctic should be thicker than usual, is extending itself into the melting season
You have shown that this is true for the Canadian archipelago, but a look at, for example, the Uni Bremen ice concentration map (for some reason not being updated on your excellent daily graphs page) shows very rapid sea-ice retreat on the Alaskan and mainland Canadian coasts - equal to what is happening on the Siberian side of the Arctic.

That's quite surprising isn't it?

Neven

I was indeed surprised to see the ice in the Beaufort Sea retreat so easily, but the data from the IceBridge mission (from EM-birds hanging from planes, see graph) shows that the ice isn't exceptionally big there.

All of our hopes seem to rest on the ice in the Canadian Archipelago, and the chunk of MYI in the Arctic Basin. And the weather, of course.

It's going to switch now, so it will be interesting to see what that does to SIE and SIA decrease. No Beaufort Gyre on the one hand, but a big low over the Central Arctic and Beaufort, and a high over Kara/Laptev.

FrankD

These are big thick blocks held in place by first-year glue, but it takes a long time for the melt to progress that far north and often they will not make it very far before getting frozen in again. The channels are mostly more open at the north than the south, so large floes can enter and get stuck between islands for long periods. But when these channels open they can shift quite a bit of ice quite a long way.

For example, in 2010 I followed a large floe that had been locked in east of Byam Martin Island. It had originated several years earlier in the Basin and was so big it had become jammed in the channel until it degraded enough to come loose in 2010. It can be seen in place on day 193. By Day 203 it had broken free into the NWP, and at 800 sq km's was the biggest single chunk of mobile ice in the area. Over the next two months it drifted towards the eastern exits of the NWP and then abruptly reversed course. Some floes that were keeping it company eventually exited the NWP between Banks and Melville (the NW end of the passage) having traversed almost its entire length, but this one got diverted by an eddy and instead ran down the east coast of Victoria Island. It overwintered between Victoria and King William before the combination of the melt and a storm caused it to break up and disperse in late July last year not too far from Cambridge Bay.

Other floes followed it out from the upper archipelago, and were replaced by ice from further north, all ultimately coming from the Arctic Basin. It can take several years - just like Amundsens navigation of the NWP - but absolutely it is an outlet for ice from the basin.

The "problem" is that the channels in the upper archipelago are narrower than the NWP itself, so any ice that makes it through there is too small and loose to entirely block the NWP. But if you look at Melville Island in August last year (Day 213 is pretty clear), most of the ice around the south coast entered the NWP from around Byam Martin Island. You can also see the fracturing in the main channel connecting the Basin and Viscount Melville Sound. Most of this MYI was still in the NWP when the freeze up occurred, and its presence partly accounts for the robust state of the ice currently choking the NWP. But a lot of this is in relatively small pieces and I'd be confident it will shift before the season is out.

Twemoran

The large bite out of Amunsden Gulf yesterday and the high temperatures don't look good for the west end.

The low pressure area over Foxe Basin may do some damage to Lancaster Sound & The Gulf of Boothia in the short term, then on the 22nd a spring tide could play havoc with everything.

I think that by the end of the month we'll see considerable progress opening things up from both ends, possibly more in the southerly route.

Terry

Neven

I'd just noticed within the Regional Search Outlooks that, due to low air temps over winter, there is a prediction from some reputable source that the Nares ice bridge will survive until mid-July - much later than in some previous years.

I was expecting that ice arch in Nares to go before last year's arch. They look very similar, but the ice looked weaker to me up till April 7th, when Envisat stopped sending images. That said, I'm not so sure anymore, despite a bite out of the arch on one end, and a polynya near the other end (which seems to have frozen over again!).

We'll see. I'm checking it out every day now.

Espen Olsen

For some strange reason, Nares, compared to everywhere else up there, looks very strong and solid, and I do not expect anything special in the strait for the rest of this month.

idunno

Hi neven,

"I'm checking it out every day now."

Yeah me too, but this guy...

http://www.arcus.org/files/search/sea-ice-outlook/2012/06/pdf/regional/gudmandsen.pdf

...thinks we're wasting our time.

Neven

Well, if I'm not mistaken, Environment Canada predicted Nares to open up much later last year too.

Eli Rabett

It is right scary how Baffin Bay is opening up in the last few days.

Pete Williamson

I'd been watching Nares Ice bridge as well expect I hadn't looked for a week or two. Things look like they;ve changed around the bridge a fair bit.

It's been like this since March
http://ocean.dmi.dk/arctic/images/MODIS/Kane/20120524TERR.jpg

Then over the course of a week it turns into this

http://ocean.dmi.dk/arctic/images/MODIS/Kane/20120612TERR.jpg

(more of that blue ice)

Pete Williamson

Thinking about it I guess that could just be snow melt revealing less homogeneous ice underneath??

Neven

It is right scary how Baffin Bay is opening up in the last few days.

That's what you get when there is no ice transport from Nares Strait and Lancaster Sound into Baffin because of stubborn ice bridges. :-)

Misfratz.wordpress.com

I thought other people might be interested in the OSTIA SST anomalies around the Canadian Archipelago.

This corresponds to absolute temperatures of +1C over a very wide region, so while the air temperatures have been low, there appears to have been an inflow of warm water - assuming we trust OSTIA in this region.

Mike Constable

On last years Northwest Passage animation I put a link to a sailwx tracker on part of the Ayles ice shelf. If you put the time up at 20000-30000 hours + you can see how it wandered through and out of the passage for the last couple of years. (I did try to link to the picture of the track but it just seems to revert to a link to the sailwx site - can anyone fix it?).
http://sailwx.info/shiptrack/shipposition.phtml?call=47554

FrankD

Anyone else notice that the bridge changed yesterday? The front edge had been somewhat jagged on the satellite image for a while, but yesterday (day 165) it suddenly became quite smooth. I wonder what (if anything) that portends.

I don't have a timeframe (total guess around the end of the month), the Ellesmere end of the bridge will collapse under the combined forces of melt from below, the expanding polynya just above it and the lateral pressure of ice from the two Ellemsere fjords (being slowly pushed forward by glaciers). Now that the snow cover is gone, the rocks and blue ice are soaking up a lot more solar heat.

Espen Olsen

The full moon tide will do the job in the end of the month.

DrTskoul

@FrankD,

I saved 1km Aqua r03c02 images for days 164 and 165 and then subtracted one of the other. There is a 1 - 2 pixel retreat of the bridge from day 164 -> 165 and about 2 - 4 pixels retreat from day 162 -> day 165. I think there is quite a bit of water flow underneath the ice and is either melting or taking some ice away from the edges of the bridge.

Espen Olsen

Dr Tskoul

If you were standing at the edge of that bridge you would probably feel like being next to dam, the current up there is really southward.

Neven

I did try to link to the picture of the track but it just seems to revert to a link to the sailwx site - can anyone fix it?

Mike Constable, here it is:

paoloc

The arc of ice at the entry of the Lancaster Sound has lost a large block (day 167 ; block that break up today : 168).
The opening of the eastern door of the NWP begins....

paoloc

Today big break in the Amundsen Gulf (and little in Mc Clure Strait)

paoloc

Two break (day 164 and today => 6 day) for break up all Amundsen Gulf!!

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