Unprecented floods on the Mississippi, in Colombia, and Canada

By: Dr. Jeff Masters , 14:58 GMT le 16 mai 2011

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The great Mississippi River flood of 2011 continues to make history, with Saturday's opening of the flood gates of the Morganza Spillway marking just the second time that flood control structure has been used since its construction in 1956. With the Morganza, Bonnet Carre', and Birds Point-New Madrid Spillways all open, the Army Corps of Engineers has now opened all of its major spillways simultaneously for the first time ever. The Mississippi is rising at Vicksburg, Mississippi, where the water has now reached 56.5', exceeding the previous all-time record of 56.2', set during the great flood of 1927. Natchez, Mississippi, is also at its greatest flood height on record, with the water at 60.6'. The previous record high was 58', set in 1937. However, the opening of the Morganza spillway has reduced the predicted heights of the great flood of 2011 from Natchez to New Orleans by 1 to 1.5'. This will serve to greatly reduce the pressure on the levees and on the Old River Control Structure, which as I discussed in my previous post, is America's Achilles' heel, and must be protected. According the National Weather Service, flood heights along the Lower Mississippi from Natchez to New Orleans will peak this week, and slowly fall next week. Rainfall over the next five days is expected to be minimal over the Lower Mississippi watershed. The next chance for significant rain over the region will come Sunday, May 22.


Figure 1. Saturday's opening of the first gate on the Morganza Spillway, as seen on the live feed from USTREAM.

Devastating flooding continues in Colombia
Devastating flooding has hit South America in Colombia, where exceptionally heavy spring rains have killed at least 425 people so far this year, with 482 others missing. Damages are in the billions, and there are 3 million disaster victims. "Some parts of the country have been set back 15 to 20 years", said Plan’s Country Director in Colombia, Gabriela Bucher. "Over the past 10 months we have registered five or six times more rainfall than usual," said the director of Colombia's weather service, Ricardo Lozano. Up to 800 mm (about 32 inches) of rain has fallen along the Pacific coast of Colombia over the past two weeks (Figure 3). The severe spring flooding follows on the heels of the heaviest fall rains in Colombia's History. Weather records go back 42 year in Colombia. Colombia's president Juan Manuel Santos said, "the tragedy the country is going through has no precedents in our history." The 2010 floods killed 571 people--the second deadliest year for floods in Colombian history, next to 1987. The floods did over $1 billion in damage, and affected 2.8 million people. In many places, the flood waters from this great disaster never fully receded, and are now rising again due to this latest round of intense flooding. More rain is in the forecast--the latest forecast from the GFS model calls for an additional 5 - 10 inches (200 - 400 mm) across much of western and northern Colombia in the coming week.


Figure 2. Satellite-observed rainfall over Colombia during the past two weeks shows a region of up to 800 mm (about 32 inches) has fallen near the Pacific coast. Image credit: Navy Research Lab, Monterey.

Colombia's rainy season usually has two peaks: one the fall in October, then then another in the spring in April - May. The heavy rains are due to the presence of the Intertropical Convergence Zone, the area encircling the earth near the Equator where winds originating in the northern and southern hemispheres come together. When these great wind belts come together (or "converge", thus the name "Convergence Zone"), the converging air is forced upwards, since it has nowhere else to go. The rising air fuels strong thunderstorm updrafts, creating a band of very heavy storms capable of causing heavy flooding rains. In La Niña years, when a large region of colder than average water is off the Pacific coast of Colombia, rainfall tends to increase over Colombia. La Niña was moderate to strong during the fall 2010 rains and floods in Colombia, and was largely to blame for Colombia's deadly rainy season. However, in recent months, La Niña has waned. April sea surface temperatures off the Pacific coast of Colombia (0° - 10°N, 85° - 75°W), warmed to the 13th highest temperatures in the past 100 years, 0.68°C above average. Thus, this month's flooding in Colombia may not be due to La Niña.

See also my December 2010 post, Heaviest rains in Colombia's history trigger deadly landslide; 145 dead or missing


Figure 3. Dramatic video of flooding in Colombia over the weekend. Flood waters swept away cars and buses in a busy street in the city of Barranquilla, and passengers climbed on the roofs of their vehicles in order to escape the flood waters. Video credit: BBC.

300-year flood in Canada; wildfires destroy large portions of Slave Lake, Alberta
In Manitoba, Canada, heavy spring snow melt in combination with heavy rains have combined to create record flooding on the Assiniboine River. Authorities intentionally breached a levee over the weekend to save hundreds of homes, but inundated huge areas of farmland as a result. The flood is being called a 300-year flood, and damages are already in excess of $1 billion. In Alberta, Canada, reverse extreme is causing havoc: severe drought and strong spring winds have made ideal conditions for wildfires, which swept into the community of Slave Lake (population 6,700) yesterday. The fires destroyed hundreds of buildings, burning down the town hall and at least 30% of the town, according to preliminary media reports.


Figure 4. Video of the May 15, 2011 Slave Lake fire.

First tropical wave of the year over the Atlantic
The first tropical wave of 2011 is now over the tropical Atlantic near 6°N 46°W, according to the latest Atlantic Tropical Weather Discussion. The wave will bring heavy rain to the northeast coast of South America over the next two days, but is too far south to be a threat to develop into a tropical depression. The Atlantic hurricane season is just two weeks away, and the Eastern Pacific hurricane season began yesterday. So far, the models are not predicting any tropical storm development in the East Pacific or Atlantic over the next six days.

Jeff Masters

The Great Flood of 2011 (jperilloux)
KCS train crossing the trestle through the Bonnet Carre Spillway at Norco, LA. Flood water diverted from Miss. River
The Great Flood of 2011

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Member Since: Posts: Comments:
Quoting nigel20:


Really heated up in the past week or so.
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Quoting RastaSteve:


I'm leaving on the Allure Of The Seas on 6/5 going to Labadee, Jamaica, and Cozumel. I'm sure this will be a wet trip as by the rainy season will for sure be going strong from FL down thru the Caribbean.


Maybe the Carnival Ecstasy on June 2nd from Galveston, to Cozumel, and back to Galveston on the 6th.
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Quoting USAprimeCreditPeggy:
KeysieLife, thank you.


No prob...I'll take the hat. =)
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Quoting USAprimeCreditPeggy:
I need to find an avatar of Peggy.


How 'bout this?

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hmmm hurricane strike
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What's long range models showing for Yucatan area around June 2nd thru June 6th? might be going on cruise in the Gulf there.
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87. JeffMasters (Admin)
Quoting DestinJeff:
Thanks. Over the next SIX days! Not seven anymore?


The GFS was maybe showing something in the EPAC in 7 days, which none of the other models were, so I got lazy and just said six days, since I didn't think the GFS forecast was worth bringing up.

Jeff Masters
Quoting USAprimeCreditPeggy:
I need to find an avatar of Peggy.
Hope this works.
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Don't think you are so far away that I can't track you down Peggy! Sincerely, Bobby Bowden
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Quoting wunderkidcayman:
BTW does any of what I said you get just wanting to know


The best part of your statement is that the eastern trough will be lifting out,Good riddance.I haven't seen the sun except for a glimpse in the past week and a half.
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Quoting wunderkidcayman:
BTW does any of what I said you get just wanting to know

Loud and Clear...
Member Since: 24 octobre 2005 Posts: 0 Comments: 23080
Awesome pics Skye,it must be incredible to hear that thunderous roar.Have talked to people who have seen others and they say it does shake every bone in your body.Thanks for the great pics.
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BTW does any of what I said you get just wanting to know
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77. Skyepony (Mod)
Thanks everyone. The shuttles are louder, rattle ya inside more than the other launches from there. It hit the cloud deck & disappeared for a 1/2 a minute or so.. Leaving full attention to the anticipation of the launch sound rolling toward us. Just waiting to be shook by it, maybe for the last time. Hope I win a placard next time too, to be close enough to feel it like that.

PalmBay~ We were parked lucky. Got right out. I was going south on SR3 under 528 & 520 before it even backed up or the media scared everyone into not going.
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YAY GFS has an EPAC system.

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Now we need to build a levee system from the Morganza spillway all the way to the Gulf,just in case another 500 year flood hits! lol
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Member Since: 8 juillet 2005 Posts: 259 Comments: 23012
peggy- I had to do a little googling but your handle is cool
Member Since: 13 août 2005 Posts: 163 Comments: 25506
a picture I took this morning of the shuttle's launch from siesta key in sarasota along florida's west coast,got lucky as their where clouds to our north and south and we had a clear slot!!!


Member Since: 5 octobre 2007 Posts: 20 Comments: 4970
Quoting aquak9:
(pottery)


((XX))
Member Since: 24 octobre 2005 Posts: 0 Comments: 23080
hey guys good morning I say this with the MJO setting in and the latest ensemble guidance continues to point towards a trough of low pressure lifting out of the eastern United States later this week into this weekend and being replaced by a ridge of high pressure if this happen it may cause a lowering in the barometric pressures over the western Caribbean as we get into next week. I think this will cause an increase in thunderstorm activity and possibly some sort of low pressure system forming in the western Caribbean towards Thursday and Friday of next week. just just like what someone said earler with a low foecasted to move NNW in thhe Western Carib in generally the same time.
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Quoting USAprimeCreditPeggy:
I have one problem. Can you help me, my card is having a problem LOL?

Sure, I can send you a keychain or a truckers cap. Chicks dig them.


LOL
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
Quoting USAprimeCreditPeggy:
Are the fires in the Everglades still going?


I believe so. They've made nice sunsets here in PBC.
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
Quoting Skyepony:
I made it to the shuttle Launch this morning..took some pics for ya'll. Will get the rest up in a bit.


Really great photo Skyepony! Thanks! Also thank you for all of the informative posts that you provide on here. :)
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Quoting USAprimeCreditPeggy:
#48

Nice!


Welcome to the blog.

I have one problem. Can you help me, my card is having a problem LOL?
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
(pottery)
Member Since: 13 août 2005 Posts: 163 Comments: 25506
Quoting aquak9:
Here we go again.

Ya'll know what to do.


Did it already.

This is sad.....
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553

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About JeffMasters

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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