Fabled Northwest Passage begins to re-freeze

By: Dr. Jeff Masters , 2:29 PM GMT on October 12, 2007

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This summer's dramatic loss of Arctic sea ice peaked on September 15, and the polar ice cap is finally beginning to re-freeze, according to a press release issued by the National Snow and Ice Data Center on October 1. Extent of the September polar sea ice fell 39%, compared to the 1979-2000 average. To put this loss in perspective, in one year we lost as much ice as we lost during the previous 28 years. Summertime Arctic sea ice is now at 50% of what it was in the 1950s (Figure 1). One may look at at graph and wonder, but what about sea ice loss in other seasons? It hasn't been nearly so severe. True, but it is the summer ice we care most about, since summer is when the thick, multi-year ice melts, which can then precondition the Arctic for much greater ice loss in future years. As sea ice melts in response to rising temperatures, more of the dark ocean is exposed, allowing it to absorb more of the sun's energy. This further increases air temperatures, ocean temperatures, and ice melt in a process know as the "ice-albedo feedback" (albedo means how much sunlight a surface reflects). There is an excellent chance that the summer of 2007 will be remembered as the "tipping point" for Arctic sea ice, when an irreversible ice-albedo feedback process firmly established itself.



Figure 1. Arctic sea ice extent since 1900, as estimated from satellite and ship reports compiled by Walsh and Chapman (2001). Image credit: University of Illinois cryosphere group.

Northwest Passage opens for the first time in recorded history
Long before the Panama and Suez Canals made commercial trading between the Atlantic and Pacific Oceans economically feasible, ships made the long and perilous trip around the African and South America continents. Explorers, traders, and world leaders looking for faster and less dangerous shipping routes to far-away areas of the world have long eyed two routes through the ice-choked Arctic Ocean--the fabled Northwest Passage, through the cold Arctic waters north of Canada, and the Northeast Passage, extending along the northern coast of Russia. The first recorded attempt to find and sail the Northwest Passage was in 1497, and ended in failure. The thick ice choking the waterways thwarted all attempts at passage for the next four centuries. Finally, in 1905, Roald Amundsen completed the first successful navigation of the Northwest Passage. It took his ship two-and-a-half years to navigate through narrow passages of open water, and his ship spent two cold, dark winters locked in the ice during the feat. More recently, icebreakers and ice-strengthened ships have on occasion battered their way through the ice-blocked route.



Figure 2. The Northwest Passage shipping route (red line) and Northeast Passage (green line) superimposed on an ice coverage map from August 22, 2007. The Northwest Passage was ice-free and navigable for 36 days between August 14 and September 18, 2007. The Northeast Passage was blocked by a narrow strip of ice most of the summer. Image credit: National Snow and Ice Data Center.

Times are changing. In 2001, the Bering Strait, a key portion of both the Northwest and Northeast Passages, was completely ice free. This was followed in 2005 by record-breaking sea-ice melt in the Arctic, leading to the first ever recorded opening of the Northeast Passage. The fabled Northwest Passage remained closed in 2005. Arctic ice recovered a bit in 2006, and both passages remained closed. But the unprecedented melting during the summer of 2007 saw the Northwest Passage become ice-free and navigable along its entire length without the need for an icebreaker as of August 14, 2007. Remarkably, the Northwest Passage remained ice-free for 36 days, finally refreezing over a small section on September 19. The Northeast Passage was blocked by a narrow strip of ice all summer. However, this strip of ice thinned to just 30% coverage on September 25 and 26, making the Northeast Passage passable for ordinary ships on those days.

When is the last time the Northwest Passage was open?
We can be sure the Northwest Passage was never open from 1900 on, as we have detailed ice edge records from ships. It is very unlikely the Passage was open between 1497 and 1900, since this was a cold period in the northern latitudes known as "The Little Ice Age". Ships periodically attempted the Passage and were foiled during this period, and the native Inuit people have no historical tales of the Passage being navigable at any time in the past.

A good candidate for the last previous opening of the Northwest Passage was the period 5,000-7,000 years ago, when the Earth's orbital variations brought more sunlight to the Arctic in summer than at present. Prior to that, the Passage was probably open during the last inter-glacial period, 120,000 years ago. Temperatures then were 2-3 degrees Centigrade higher than present-day temperatures, and sea levels were 4-6 meters higher.

Final thoughts
If we have reached the tipping point for Arctic ice, what are the implications? I'll discuss this more in a future blog. Sea ice is very complicated, and it is not a sure thing that we have reached the tipping point. For more on the complexities of sea ice, read wunderblogger Dr. Ricky Rood's latest blog.

NASA has posted a beautiful satellite image of the Arctic ice cap at the September 15 2007 minimum, showing the open water of the Northwest Passage.

I thank Edalin Michael of the University of Michigan's School of Natural Resources and Robert Grumbine of NOAA's Sea Ice Group for their contributions to this blog.

References
Walsh, J.E and W.L.Chapman, 2001, "Twentieth-century sea ice variations from observational data", Annals of Glaciology, 33, Number 1, January 2001 , pp. 444-448.

Jeff Masters

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797. Weather456
8:15 PM AST on October 12, 2007
Tropical Disturbance 01 heading towards N Madagascar.

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796. BahaHurican
8:05 PM EDT on October 12, 2007
UYA, the Banco Chinchorro is an atoll off the east coast of the Yucatan in between Cozumel and Chetumal.

Google it. There are some great photos and maps available.
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795. 0741
12:06 AM GMT on October 13, 2007
i heard here on news that alot people dead in haiti because of flood all rain from nw carribbean
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794. Weather456
8:02 PM AST on October 12, 2007
94L



37V - temperature from heat generated by condensation. Does not work well overland where u have heating from daytime.

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793. moonlightcowboy
12:04 AM GMT on October 13, 2007
Hey, A'sG, this has been a big area of low pressure. Had 94L stayed over water instead of going inland the first part of the week, even despite the shear, it's possible we'd being talking about at hurricane that would probably be making landfall now somewhere around the GOM.

The thing is, that's exactly what we still might be doing later this next week, too. But, there are some ragged conditions. First, as the low re-enters the Caribbean over warm waters, it'll most likely show signs of strengthening. Steering currents are very weak now in that area, so it's liable to linger, further making the case for a stronger storm.

Of course, there's "Mariah Winds" (lol) over the GOM right now, 50-60 kts. Nothing can hardly go in that direction and grow-only weaken. So, it'll depend on how long it lingers over warm waters, how fast the shear moves out and if there are any other fronts that may come into play. But, development is surely possible.

Haven't had much chance to study all of it. Earlier this week I was almost certain that 94L was going to emerge off the Yucatan and into the wCarib, and I expressed my thoughts, well, let's say a little less conservatively. So, well, I missed that, as 94L went south, but it's still trying to make a comeback and still warrants a close, watchful eye.

Thanks for asking! Take care.
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792. weathers4me
12:07 AM GMT on October 13, 2007
Once former 94l emerges into the GOM it will be the next depression IMO. Night all.
Member Since: May 24, 2007 Posts: 0 Comments: 118
791. weathermanwannabe
7:05 PM EST on October 12, 2007
Just popping in for a sec after a long day at work.......I do think that Dr. M is "da man" so if this "sleeping giant" concept, that he has been advocating for almost a week now, does result in some type of depression forming in the Gulf, I'll be even more impressed with him........
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790. UYA
12:06 AM GMT on October 13, 2007
Banco Chinchorro is an atoll reef near Belize that is one of the world's premiere shipwreck diving spots. The reef, which lies in Mexican waters in the Caribbean Sea, is home to at least nine shipwrecks, including two Spanish Galleons.


Right, why didn't ya say so? LOL
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789. UYA
12:01 AM GMT on October 13, 2007
A SURFACE TROUGH EXTENDS NORTHEASTWARD FROM A 1005 MB
NORTH CENTRAL GUATEMALA LOW PRESSURE CENTER TO A 1004 MB LOW
PRESSURE CENTER NEAR 19N87W AT THE NORTHERN EDGE OF THE BANCO
CHINCHORRO...TO CUBA NEAR 22N80W AND BEYOND INTO THE ATLANTIC
OCEAN. STRONG SHOWERS/THUNDERSTORMS ARE SOUTH OF 17N WEST OF 86W
INCLUDING IN THE GULF OF HONDURAS.



Alright....where the heck is this?.......AT THE NORTHERN EDGE OF THE BANCO
CHINCHORRO.
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788. moonlightcowboy
11:59 PM GMT on October 12, 2007
771. UYA 11:33 PM GMT on October 12, 2007 Hide this comment.
Well, Cowboy......when a new 1004mb low just kind of pops up on the 2:05 NHC discussion off the coast of Belize and is stationary.....during a positive MJO cycle, I get interested.
Know what I mean?


...definitely watching.
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787. UYA
11:58 PM GMT on October 12, 2007
No, Baha it doesn't deepen at all. Hoping for something maybe that could drag some moisture up that way. That would be Perfecto.
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786. icmoore
11:59 PM GMT on October 12, 2007
Sleep well and feel better, StormW!
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785. aubiesgirl
11:59 PM GMT on October 12, 2007
So 94L has a lil spin goin on..might head NNE...intereting..MLC what is your take?
783. Weather456
7:56 PM AST on October 12, 2007
LINGLING

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782. BahaHurican
7:53 PM EDT on October 12, 2007
GFS doesn't deepen that very much, does it?
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781. Weather456
7:51 PM AST on October 12, 2007
This blog is singing Britney spears new song

Gimme Gimme More

15 was enough
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779. CaneAddict
11:48 PM GMT on October 12, 2007
Good evening folks!
Member Since: October 5, 2007 Posts: 3 Comments: 2151
778. UYA
11:51 PM GMT on October 12, 2007

Photobucket - Video and Image Hosting



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777. TampaSpin
11:48 PM GMT on October 12, 2007
Am i correct to say that strong sheer moves in very fast this time of year.
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776. ryang
7:40 PM AST on October 12, 2007
My Tropical Update...
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775. UYA
11:39 PM GMT on October 12, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL

TUE-THU...EXTENDED GFS MODEL RUNS REMAIN ANYTHING BUT CONSISTENT.
THE UPPER FLOW WILL FLATTEN OUT DURING THIS TIME AS A PLETHORA OF
MID-LEVEL ENERGY SKIRTS THE MIDDLE PART OF THE COUNTRY. MOISTURE
WILL BEGIN TO INCREASE OVER THE AREA FROM THE SOUTH ON TUE AHEAD OF
A PSEUDO WARM FRONT THAT IS FORECAST TO MOVE NORTH ACROSS THE
PENINSULA FROM SOUTH FLORIDA AS LOW PRESSURE DEVELOPS OVER THE
NORTHEAST GULF.
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774. SamTeam
6:39 PM CDT on October 12, 2007
Hi guys

Is it safe to come back??? When I was here about 3:30 & the WU was the eHarmony site. :)

What's the latest on ex 94? I'm trying to read back thru to catch up!

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773. stormybil
11:38 PM GMT on October 12, 2007
gfs showing a storm for fla ?
Link
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772. nrtiwlnvragn
11:36 PM GMT on October 12, 2007
24, 48 and 72 hour surface forecasts.
Member Since: September 23, 2005 Posts: 15 Comments: 11343
771. UYA
11:31 PM GMT on October 12, 2007
Well, Cowboy......when a new 1004mb low just kind of pops up on the 2:05 NHC discussion off the coast of Belize and is stationary.....during a positive MJO cycle, I get interested.
Know what I mean?
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770. Drakoen
7:30 PM EDT on October 12, 2007
The low to the north near Cozumel will probably dissapate. Shear is too strong.
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769. Weather456
7:29 PM AST on October 12, 2007
A broad area of low pressure centered on two surface lows which is expected to move to the NNE into the SE Gulf. Current shear is near 60 Knots in the E Gulf...this is being created by the flow around the northern periphery of an upper level anticyclone over the NW Caribbean. Development seems possible however....The shear zone in the Gulf is progressing eastward...shear is forecast to drop a fairly good amount in 48 hrs time. About the same tme the low should be near the Yucatan Channel.



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768. hurrhunter
11:25 PM GMT on October 12, 2007
what is up with all this rain in cayman
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767. TampaSpin
11:25 PM GMT on October 12, 2007
The blob at 70/15 should move WNW. Does anyone think that the energy of 94L and the blob could combine to aid development or is that possible.
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766. KEEPEROFTHEGATE (Mod)
11:16 PM GMT on October 12, 2007
as nw'er tracks se towards four corners from n ca it may cause a strong wave to pop up in gom tue wed over gom then track ene over fla /bahamas western atlantic starting fri/sat the current split flow block causing system in ca to slide under there fore a westerly flow is beginning to look more possible as we move thur oct
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765. Drakoen
7:23 PM EDT on October 12, 2007

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764. UYA
11:21 PM GMT on October 12, 2007
--UYA, 94L may be coming back, afterall. That front you talked about first of the week, brought us into the 40's temps here. Actually turned the heat on.

You were the one calling for this current low in the NW Carib my friend......back on Tuesday. Nice shot!

I'm jealous about the cool weather.......
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763. BahaHurican
7:20 PM EDT on October 12, 2007
Both storms' eyes passed over the house of a friend of mine. She later said after Frances, she actually fared quite well in Jeanne mainly because there wasn't much left in the way of trees etc. to blow down. Plus her power etc. was already out . . .
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762. HurricaneGeek
7:22 PM EDT on October 12, 2007
And when (if) it does be an invest where it headed?
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761. TampaSpin
11:19 PM GMT on October 12, 2007
I would think X94L would become an invest and have a floater again sooner than later IMO.
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760. Weather456
7:20 PM AST on October 12, 2007
15L has on its birthday suit.

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759. BahaHurican
7:17 PM EDT on October 12, 2007
Those two storms hit almost the same places coming into that FL landfall as well, almost as if Frances had cleared a path for Jeanne.
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758. HurricaneGeek
7:19 PM EDT on October 12, 2007
Yeah, that's about a quarter mile North of Frances or less.
-----
I walk LONGER than that to school!! LOL
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757. moonlightcowboy
11:17 PM GMT on October 12, 2007
Good evening, UYA and Baha.

--UYA, 94L may be coming back, afterall. That front you talked about first of the week, brought us into the 40's temps here. Actually turned the heat on.

--Katadman, thanks, tons! Definitely interested in how their trip is going and what the relief effort is like.
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755. BahaHurican
7:07 PM EDT on October 12, 2007
Storm, that's on the coast side of the Bay right? Near Clearwater somewhere.
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754. Weather456
7:16 PM AST on October 12, 2007
Tropical Disturbance 01R: These ppl are kidding if they called this a disturbance with 35+ knot winds

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753. UYA
11:10 PM GMT on October 12, 2007
At 1 am EDT on September 5 (0500 UTC), the center of the broad eye of Frances finally was over Florida, near Sewall's Point, FL.


At 11:50 p.m. EDT September 25 (0350 UTC September 26), Jeanne made landfall on Hutchinson Island, FL.



Yeah, that's about a quarter mile North of Frances or less.


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752. katadman
6:13 PM CDT on October 12, 2007
Howdy, MLC. Tried to contact my wife in Nicaragua for an update, but she is in transit and couldn't be reached. I'll bring you up to date on the Felix effort as soon as I have info.
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751. kmanislander
11:14 PM GMT on October 12, 2007
Incidentally, pressures are still low in the NW Caribbean. 1006.3 here now
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750. moonlightcowboy
11:13 PM GMT on October 12, 2007
Hey, Katadman! Get us a CA report! TIA

--K'man, eyes will be on that system over the weekend for sure!
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749. TampaSpin
11:12 PM GMT on October 12, 2007
Drak-
looking at steering it would appear that EX94L would probably move NNE slowly if anything IMO.
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748. katadman
6:05 PM CDT on October 12, 2007
Later, Flood & Nash.

Hi, Storm W. Have any news beyond your latest synopsis?
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747. kmanislander
11:11 PM GMT on October 12, 2007
Hi MLC

We are approaching the secondary peak in oct. The next 10 days will tell the tale and I also expect a Nov surprise with the strong La Nina.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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