Dr. Jeff Masters' WunderBlog

Unprecented floods on the Mississippi, in Colombia, and Canada

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

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

Categories: Flood

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251. KEEPEROFTHEGATE (Mod) 21:24 GMT le 16 mai 2011
Member Since: 15 juillet 2006 Posts: 143 Comments: 40425

252. Levi32 21:25 GMT le 16 mai 2011
Quoting alfabob: This is what I'm seeing, arrows are low/mid level winds. I'm giving it a 60% chance to develop over the next 24 hours. The very broad low- mid-level circulation is located all the way back at ~5.5N ~104.5W. Imminent development is unlikely. Loop Member Since: 24 novembre 2005 Posts: 586 Comments: 25441

253. pottery 21:26 GMT le 16 mai 2011
Quoting RitaEvac: Like a broken record, is it ever gonna rain in TX? Sure is! In August.... heheheh Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

254. alexhurricane1991 21:26 GMT le 16 mai 2011
Quoting Levi32: The very broad low- mid-level circulation is located all the way back at ~5.5N ~104.5W. Loop No development in the near term. Member Since: 8 avril 2010 Posts: 15 Comments: 2543

255. pottery 21:28 GMT le 16 mai 2011
Quoting KEEPEROFTHEGATE: Nice! Let us know the Outcome of that. Whatever it might be. Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

256. hurricaneben 21:29 GMT le 16 mai 2011
Quoting Levi32: The very broad low- mid-level circulation is located all the way back at ~5.5N ~104.5W. Imminent development is unlikely. Loop Well...I doubt it'd become a TD within', say, 12 hours or so (that's unlikely but not impossible) however it is very possible to even likely that a TWO will be issued on it and the NHC will give it a yellow or orange circle sometime tomorrow possibly. And I'd say there is a 40-60% chance of this becoming a TD or TS within' the next 4 days, a 5% chance of tonight. Member Since: 15 mai 2009 Posts: 330 Comments: 597

257. Stormchaser2007 21:31 GMT le 16 mai 2011
EUROSIP from yesterday: Warm-biased neutral: Member Since: 9 juin 2007 Posts: 4 Comments: 15243

258. Minnemike 21:32 GMT le 16 mai 2011
Quoting KEEPEROFTHEGATE: oh good, this addresses my inner most thoughts ;) Member Since: 31 juillet 2008 Posts: 0 Comments: 1254

262. hurricaneben 21:37 GMT le 16 mai 2011
Quoting alfabob: This is what I'm seeing, arrows are low/mid level winds. I'm giving it a 60% chance to develop over the next 24 hours. I'd give it a bit less than that, but nowhere near 0%. Probably around 20-50%. I think it has a very darn good shot at development by mid to late week. The NHC might as well put up a circle for it tomorrow. Member Since: 15 mai 2009 Posts: 330 Comments: 597

264. Levi32 21:41 GMT le 16 mai 2011
Quoting alfabob: I'm seeing a LLC around 8N, 100W which came from the burst of convection yesterday; and another more broad circulation to the N/NE of it. The other broad low to the SW though may prohibit development, but I'm not expecting the low that is labeled to actually develop. I see no low-level rotation at those coordinates. There is a hint at a left-over MLC from the initial burst of convection, but it is currently dissipating and has no connection to the surface. Member Since: 24 novembre 2005 Posts: 586 Comments: 25441

266. hurricaneben 21:55 GMT le 16 mai 2011
Quoting alfabob: Yea I messed up because I didn't notice the other low that developed next to it. But taking that into account I would say 60% over the next 2-3 days, and probably 30% over the next 24. Ya and I made a blog about it just now--just in case you wanna check it out. I do think the NHC might put a circle around it within' the next 24 hours and a TD/TS--not so likely but then again not impossible within' 24 hours. Within' 72 hours, very possible. Member Since: 15 mai 2009 Posts: 330 Comments: 597

267. Levi32 22:23 GMT le 16 mai 2011
Disorganized, but nice to see the EPAC ITCZ heating up. Member Since: 24 novembre 2005 Posts: 586 Comments: 25441

268. cyclonekid 22:26 GMT le 16 mai 2011
Quoting alfabob: Couldn't clearly see the other circulation with the image I was using, but I think the ASCAT may have mis-read some of the winds (or they are for the upper-atmosphere). It looks cyclonic on RGB instead of anti (just a change in wind direction); but it may dissipate faster due to another cyclone to its west. If the AOI manages to stay in 30C waters, it should be able to start dropping pressure and picking up wind speeds. It's easy for a system to look like a tropical system, but all systems that mock a tropical cyclone may not have a circulation center under the convection that looks like it may have one. Make sense? Member Since: 14 juillet 2009 Posts: 51 Comments: 1626

269. aquak9 22:48 GMT le 16 mai 2011
I see the praying only helped a little. Peggy's gone? Dangblast it, I found her an awesome shower curtain on Ebay. Bidding's hard and heavy. Member Since: 13 août 2005 Posts: 163 Comments: 25006

271. BahaHurican 22:54 GMT le 16 mai 2011
Evening all. Back after a long, long day. Quoting kwgirl: Good morning everyone. Well, yesterday when that front moved through the Keys, I was very hopeful that we would get some rain. Had clouds, thunder, cooler air, and 15 drops of rain. Then the sun came out. So disappointing. So BahaHurican, don't get your hopes up. I can't wait for one of our frog strangling downpours. I will be dancing in the street, until I have to dog paddle:) kwgirl, between the time I made that post and the time I left for work this morning, the front dropped about the same 15 drops of rain on my car. It was just enough to make spots in the dust on the car... and was dry before I got to work. [sigh...] I guess the earlier forecast of 60% chance of rain has fizzled, too.... it's dry up and down this archipelago... and looking like we will have to wait for a tropical entity to break the pattern. Now I'll go read a few posts.... lol Member Since: 25 octobre 2005 Posts: 19 Comments: 17605

272. Tazmanian 22:56 GMT le 16 mai 2011
Quoting USAprimeCreditPeggy: If you friend him on facebook, do you get a free shower curtain? LOL Member Since: 21 mai 2006 Posts: 5088 Comments: 111327

274. aquak9 22:58 GMT le 16 mai 2011
Sorry Peggy- they only had 27 of them, and they're all sold. :) I tried!! Member Since: 13 août 2005 Posts: 163 Comments: 25006

277. WatchingThisOne 23:01 GMT le 16 mai 2011
Quoting pottery: The approach of 'Hurricane Season' seems to coincide with the start of 'Idiot Season'. A strange phenomenon, probably related to Climate Change, which as everyone knows, brings on Blogitis Maxima. As you know, this is Contagious, Fatal, and Supremely Annoying. In that order. Take your Pills, say a Prayer, and hope you Survive..... The last month or two have been great for updating the old ignore list and I have the filters ready to go. For those who slip by, I also have a wooden mallot to hit myself over the head with. Here's to an interesting season. WTO Member Since: 15 juillet 2005 Posts: 3 Comments: 1249

278. WatchingThisOne 23:01 GMT le 16 mai 2011
. Member Since: 15 juillet 2005 Posts: 3 Comments: 1249

279. aquak9 23:02 GMT le 16 mai 2011
blue background, tropical fish, and even a studly dude in black leather to come install them. Sigh....I appreciate your humor too, Peggy. Member Since: 13 août 2005 Posts: 163 Comments: 25006

281. cyclonekid 23:04 GMT le 16 mai 2011
Quoting alfabob: I know that, the only reason I'm saying this has a circulation is because I watched it form; and I could faintly see it under the cloud cover. I wouldn't consider something attached to the ITCZ an AOI if it was just random thunderstorms showing up. This thing has been around for 36-48 hours now and is still building convection/organizing. Yea I noticed that about the same time. Persistence is the key to the NHC using their yellow crayon. Give it about a day or two to get organized, we might see the crayon pop out then. Member Since: 14 juillet 2009 Posts: 51 Comments: 1626

284. BahaHurican 23:09 GMT le 16 mai 2011
Hmmm.... potential tropical something in the EPac already??? Granted, SSTs look good enough. While one never knows, I think I'll be giving more of an eye to that Twave #1 - if it makes it W of Panama.... and sadly, it looks like that #1 will be contributing some more rain to Columbia. Member Since: 25 octobre 2005 Posts: 19 Comments: 17605

286. msgambler 23:14 GMT le 16 mai 2011
Quoting aquak9: blue background, tropical fish, and even a studly dude in black leather to come install them. Sigh....I appreciate your humor too, Peggy. The horror of it all,I tell ya Member Since: 27 février 2010 Posts: 0 Comments: 1120

288. pottery 23:23 GMT le 16 mai 2011
Quoting StAugustineFL: Reality really sucks, man. Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

289. ShenValleyFlyFish 23:27 GMT le 16 mai 2011
Quoting pottery: Reality really sucks, man. Great bumper sticker: Question Reality Member Since: 9 septembre 2007 Posts: 36 Comments: 4684

290. Jedkins01 23:29 GMT le 16 mai 2011
Quoting StAugustineFL: that's probably one of my many favorite pictures haha Member Since: 21 août 2008 Posts: 0 Comments: 5322

291. KEEPEROFTHEGATE (Mod) 23:36 GMT le 16 mai 2011
Quoting pottery: Reality really sucks, man. ya sometimes but dont worry it comes back everyday as somebody else Member Since: 15 juillet 2006 Posts: 143 Comments: 40425

292. Patrap 23:37 GMT le 16 mai 2011
Video: Mississippi River level holding steady at 17' in N.O. Member Since: 3 juillet 2005 Posts: 370 Comments: 111244

293. pottery 23:37 GMT le 16 mai 2011
Quoting ShenValleyFlyFish: Great bumper sticker: Question Reality Especially these days. It used to be all so simple... Now, Reality TV is the hottest form of fiction. And people swear that's it's all true. Incredible. ah, well. Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

294. pottery 23:37 GMT le 16 mai 2011
Quoting Patrap: Video: Mississippi River level holding steady at 17' in N.O. Good News, there. Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

295. Jedkins01 23:39 GMT le 16 mai 2011
Well I'm glad we had lots of strong thunderstorms and heavy rain this weekend in Florida. But with a frontal passage this strong followed by cool and dry air almost record levels, its safe to say the wet season isn't here anytime soon. Because overall well above normal temps dominated late February into early this month, and La Nina dying I thought it might mean an early start to Florida's wet season. However it was just an educated guess pretty much, its hard to actually forecast it anyway. Overall though, once the wet season does get cranking, I'm expecting at or above normal rainfall and a much higher amount of strong thunderstorm activity than last year. Last year we consistently stable air masses with warm air aloft and inversions even into the heart of last year. This year Florida has been dominated mostly by unstable air with cold air aloft for the most part, even when upper ridges have been in place, there has been cold air aloft. Once we get a surge of that 2.0 to to 2.25 inch PWAT air from the deep tropics like we do in the wet season. Numerous thunderstorms, many of them very strong will be plentiful in Florida. That's the way I see it. It may take quite a while longer though. Member Since: 21 août 2008 Posts: 0 Comments: 5322

296. pottery 23:42 GMT le 16 mai 2011
What happened to Grothar? Anyone know? I miss his comments. Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

297. StAugustineFL 23:42 GMT le 16 mai 2011
Quoting pottery: Reality really sucks, man. Quoting pottery: Reality really sucks, man. Family photo album circa 1987 rocking the dot matrix printer and 15" CRT monitor. Mom was a little upset when she saw the cig in my right hand. Sorry to interrupt. A light attempt at humor while things are a bit slow......... Member Since: 8 Mars 2011 Posts: 1 Comments: 567

298. Patrap 23:43 GMT le 16 mai 2011
MODIS view of Lake Pontchartrain showing the Bonnet Carre infusion into the lake from the Big Muddy.. Member Since: 3 juillet 2005 Posts: 370 Comments: 111244

299. StAugustineFL 23:46 GMT le 16 mai 2011
Quoting Jedkins01: Well I'm glad we had lots of strong thunderstorms and heavy rain this weekend in Florida. But with a frontal passage this strong followed by cool and dry air almost record levels, its safe to say the wet season isn't here anytime soon. Because overall well above normal temps dominated late February into early this month, and La Nina dying I thought it might mean an early start to Florida's wet season. However it was just an educated guess pretty much, its hard to actually forecast it anyway. Overall though, once the wet season does get cranking, I'm expecting at or above normal rainfall and a much higher amount of strong thunderstorm activity than last year. Last year we consistently stable air masses with warm air aloft and inversions even into the heart of last year. This year Florida has been dominated mostly by unstable air with cold air aloft for the most part, even when upper ridges have been in place, there has been cold air aloft. Once we get a surge of that 2.0 to to 2.25 inch PWAT air from the deep tropics like we do in the wet season. Numerous thunderstorms, many of them very strong will be plentiful in Florida. That's the way I see it. It may take quite a while longer though. Waiting patiently. Can we fast forward 2-3 weeks? Member Since: 8 Mars 2011 Posts: 1 Comments: 567

300. pottery 23:47 GMT le 16 mai 2011
Quoting StAugustineFL: Family photo album circa 1987 rocking the dot matrix printer and 15" CRT monitor. Mom was a little upset when she saw the cig in my right hand. Sorry to interrupt. A light attempt at humor while things are a bit slow......... LOL I hope Mom whacked you across the head for the cig. Sorry someone didnt do that to me.... Member Since: 24 octobre 2005 Posts: 0 Comments: 20708

301. CaicosRetiredSailor 23:52 GMT le 16 mai 2011
Satellite image of the Morganza spillway with gate(s) open http://www.washingtonpost.com/blogs/capital-weath er-gang/post/morganza-spillway-from-space-image-of -day/2011/05/16/AFLCFA5G_blog.html. original from NASA photos at: http://www.flickr.com/photos/gsfc/5727210487/in/set-7215 7626684307622/#/ The Morganza Spillway as Seen by NASA's EO-1 Satellite NASA image captured May 15, 2011 This true color image of the Morganza Spillway located 45 miles northwest of Baton Rouge, Louisiana, was captured by the Advanced Land Imager (ALI) instrument on NASA's Earth Observing (EO-1) satellite on May 15, 2011. According to ENN.com, the U.S. Army Corps of Engineers opened up two of the 125 floodgates on May 14, and two more floodgates on May 15 to relieve the floodwaters on the Mississippi River (located to the far right). The spillway channels water from the Mississippi into the Atchafalaya River basin and will alleviate flooding in New Orleans and Baton Rouge, but flood homes, farms, a wildlife refuge and a small oil refinery. Image Credit: NASA Earth Observatory/EO-1 Team, Text: NASA/Rob Gutro Member Since: 12 juillet 2007 Posts: 0 Comments: 5111

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