Two 500-year floods in 15 years

By: Dr. Jeff Masters , 2:48 PM GMT on June 19, 2008

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The U.S. Geological Survey has preliminary data showing that this month's floods on four of Iowa's rivers--the Cedar, Iowa, Shell Rock, and Wapsipinicon--were 500-year floods. Back in 1993, many rivers in the Midwest also experienced 500-year floods, so the region has endured two 500-year floods in the past 15 years. How can this be? First of all a definition--a 500-year flood is an event that has only a 0.2% chance of occurring in a given year, based on available river flow data. Of course, reliable data only goes back a century at most, so designation of a 500-year flood event is somewhat subjective. Still, it seems rather improbable that two such huge floods should occur within such a short time span, raising the question of whether the floods were, in part, human-caused.

In a provocative story in the Washington Post today, it was pointed out that part of the flooding is due to the draining of wetlands for farming purposes. As nature's natural buffers against flooding are drained and filled to provide room for more farmland, run-off and flooding are bound to increase. Furthermore, as more levees are built to protect more valuable farmland and new developments, flood waters are pushed out of the former areas they were allowed to spread out in and forced into river channels behind the new levees. Even higher levees must then be constructed to hold back the increased volume of water they are asked to contain.

Climate change contributing to flooding?
The heaviest types of rains--those likely to cause flooding--have increased in recent years (see my February blog, "The future of flooding", for more detail). According to the United Nations' Intergovernmental Panel on Climate Change (IPCC) 2007 report, "The frequency of heavy precipitation events has increased over most land areas". Indeed, global warming theory has long predicted an increase in heavy precipitation events. As the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air. According to the 2007 IPCC report, water vapor in the global atmosphere has increased by about 5% over the 20th century, and 4% since 1970.

Over the U.S., where we have very good precipitation records, annual average precipitation has increased 7% over the past century (Groisman et al., 2004). The same study also found a 14% increase in heavy (top 5%) and 20% increase in very heavy (top 1%) precipitation events over the U.S. in the past century. Kunkel et al. (2003) also found an increase in heavy precipitation events over the U.S. in recent decades, but noted that heavy precipitation events were nearly as frequent at the end of the 19th century and beginning of the 20th century, though the data is not as reliable back then. Thus, climate change is likely partly to blame for increased flooding in the U.S., although we cannot rule out long-term natural variations in precipitation.


Figure 1. Forecast change in precipitation and runoff for the period 2080 to 2099 compared to 1980 to 1999. The forecasts come from the A1B scenario from multiple climate models used for the Intergovernmental Panel on Climate Change (IPCC) 2007 report.

The forecast
According to a multi-model consensus of the climate models run for the Intergovernmental Panel on Climate Change (IPCC) 2007 report, precipitation and river runoff for the Mississippi River drainage basin are expected to increase only slightly by the end of this century (Figure 1). However, more of this rain is expected to fall in heavy precipitation events, the ones most likely to cause flooding. As a result, the U.S. needs to prepare for an increase in the number and severity of 100-year and 500-year flooding events in the coming century.

References
Kunkel, K. E., D. R. Easterling, K. Redmond, and K. Hubbard, 2003, "Temporal variations of extreme precipitation events in the United States: 1895.2000", Geophys. Res. Lett., 30(17), 1900, doi:10.1029/2003GL018052.

Groisman, P.Y., R.W. Knight, T.R. Karl, D.R. Easterling, B. Sun, and J.H. Lawrimore, 2004, "Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends Derived from In Situ Observations," J. Hydrometeor., 5, 64.85.

Tropics
It's quiet in the tropics. There are no threat areas to discuss, and none of the models are forecasting tropical storm formation in the next seven days.

Jeff Masters

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104. TEXASYANKEE43
6:57 PM GMT on June 19, 2008
103. HadesGodWyvern


That does not look good for Japan with it moving West.....
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103. HadesGodWyvern (Mod)
6:50 PM GMT on June 19, 2008
Japan Meteorological Agency
Tropical Cyclone Advisory
03:00 AM JST June 20 2008

SUBJECT: Category Three Typhoon east of the Philippines

At 18:00 PM UTC Typhoon Fengshen T0806 (980 hPa) located near 10.8N 127.6E has 10 minutes sustained winds of 65 knots with gusts up to 95 knots. The typhoon was reported moving west northwest at 12 knots.

Storm-Force Winds
===============
45 NM from the center

Gale-Force Winds
================
150 NM west from the center
120 NM east from the center

Forecast Position and Intensity
=============================
24 HRS: 13.1N 125.5E - 70 knots (CAT 3)
48 HRS: 15.3N 124.4E - 80 knots (CAT 3)
72 HRS: 17.3N 124.1E - 85 knots (CAT 4)
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102. atmoaggie
6:51 PM GMT on June 19, 2008
92:

All good points.

My problem with the Trenberth item is that if a lead author, aka editor of other's contributions, is willing to surmise non-scientific effects of GW and purport it as fact, just when does objectivity and bullet-proof truth come in?

Trenberth is a leading researcher in monsoons and very well respected, but this issue is very synonymous to a president's cabinet member making prejudicial remarks about someone's skin color...yet no uproar.
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101. Nolehead
6:52 PM GMT on June 19, 2008
myway...the panhandle is way ahead of them...as many damn storms we have had in the past few years, 1 thing we have learned is not to expect the gov't to do squat!! i applaud you and your fellow neighbors...
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100. Stormchaser2007
6:55 PM GMT on June 19, 2008
07W FENGSHEN.50kts-985mb-104N-1287E

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99. Floodman
1:54 PM CDT on June 19, 2008
98. moonlightcowboy

It's a shame, MLC, but I find that age and experience tend to kill optimism...
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98. moonlightcowboy
1:46 PM CDT on June 19, 2008
Of course, politics is in everything including science - most definitely. And, I certainly don't think one can rule out that anthropogenics is politically motivated. In the rundown, it's going to be about power and greed, no matter how you stack it up: like this Enron price-fixing scam that's being run on all of us to manipulate the price of oil and futures speculating.

A vote "against" the farm bill continued the Enron loophole. That puts McCain for price-fixing the way I see it. Unless, he comes out with a platform that nullifies, repeals that loophole and prevents such future legislation, I will NOT be voting for McCain. And, I don't like Obama either; but, he did vote for it and could have perhaps killed the Enron loophole.

That kind of price manipulation practice being fixed is N O T what this country needs and where the very special elite benefit from the depravity of the masses. I could handle pork-barrel projects much better than the latter. I won't vote for a candidate that supports the Enron loophole.

So, I guess it's going to be a matter of picking the most passionate issues and seeing which tally adds up the most. In reality, a vote for either will not really help anything in my opinion. It'll just be more of the same and I just look for things to get worse. And, that bothers me because I've always been an optimist.
Member Since: July 9, 2006 Posts: 184 Comments: 29594
97. myway
6:44 PM GMT on June 19, 2008
Towns underwater, crops wiped out, personal belongings gone, thousands have suffered. Notice however the great majority are helping the neighbors.
People helping? Not waiting for a govt. handout? Have they gone mad?
I think not. Midwesterners actually help others, normally without the poor me attachment.
Other parts of the country should learn from this.
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96. Floodman
1:43 PM CDT on June 19, 2008
"I think it's extremely difficult to pin the last season on global warming. That does not preclude that there may be a global warming signal buried in there somewhere, but nobody in my field thinks that we've seen it."


The above quote from Kevin Trenberth, in reference to the calims that the 2004 hurricane season was influenced by "GW"

A voice of reason? Again, I say that to deny that Climate Change is occurring is ridiculous, just as denying that we, as part of the system, are one of the causes is ridiculous...but on the opposite side, calling every falling leaf "further evidence of global warming" is pretty damned irresposible and ridiculous as well...
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95. guygee
6:45 PM GMT on June 19, 2008
89. atmoaggie 6:41 PM GMT on June 19, 2008

I see your point atmoaggie but look at the furor on this blog. This may be representative of the population at large. Quite a diversity of opinions. Also, no question as to where the corporate research dollars are flowing.
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94. Stormchaser2007
6:47 PM GMT on June 19, 2008
Looks like it already has an eye....

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93. Stormchaser2007
6:43 PM GMT on June 19, 2008
FENGSHEN
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92. guygee
6:40 PM GMT on June 19, 2008
Re:88

Every human organization has its politics. I would like to see an example of one that does not. It is an unfortunate fact, with repercussions we can only hope to minimize. This case seems more like a personal dispute to me, rather than some broad conspiracy.
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91. HadesGodWyvern (Mod)
6:43 PM GMT on June 19, 2008
TPPN10 PGTW 191821

A. Typhoon 07W (FENGSHEN)
B. 19/1730Z
C. 10.7N
D. 127.5E
E. THREE/MTSAT
F. T4.0/4.0/D1.5/24HRS STT: D1.0/06HRS (19/1730Z)
G. IR/EIR
13A/PBO BANDING EYE/ANMTN. SYSTEM IS DEVELOPING A WEAK
EYE, WHICH IS SUPPORTED BY AN EYE ON MICROWAVE IMAGERY.
DT IS A 4.5 BASED ON MG SURR SHADE AND OW EYE TEMP.
CONSTRAINTS LIMIT FINAL-T TO 4.0. THIS AGREES WELL WITH
RAPIDLY DEVELOPING MET AND PT OF 4.0. DBO DT WITH
CONSTRAINTS AND PT.
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90. Floodman
1:39 PM CDT on June 19, 2008
65. MonkeeInDaTrunk

BEcause there are fewer elephants, by a factor of 100, than there are cows...
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89. atmoaggie
6:36 PM GMT on June 19, 2008
atmoaggie - I am curious at to why you think a scientist pursuing a valid line of research that challenges the IPCC view would not receive an equal chance of funding?

Hey guygee.

Funding sources, such as NSF, NASA, NOAA, etc. still have to justify budgets with non-scientists...most representing the public (congress). Generating a public furor makes more money available to those generating the furor...in grants.

Researchers do ultimately have to defend the need for the work and if the need for that work is in great demand...easy button.

We would like to think that our science guys were immune to such short cuts, but I am beginning to have my doubts.
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88. atmoaggie
6:24 PM GMT on June 19, 2008
Exhibit A of the IPCC's politics here. A lead author publicly issuing an edict not scientifically supported by any peer-reviewed pubs.

The link is a good explanation of the reasons a leading researcher in the field of hurricanes resigned from the IPCC. Be sure to click "resignation" to see Landsea's entire letter to the community to get his viewpoint as a IPCC member.

IPCC's reports on TCs and a potential GW signal would have so much more credibility with Landsea. Trenberth is not a dummy, but probably should have left his mouth at home the days they were going to talk about hurricanes and records. He is primarily a monsoon and south Pacific guy.
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87. HadesGodWyvern (Mod)
6:32 PM GMT on June 19, 2008
97W.INVEST

Best status from NRL: 15kts 1010 mb
97W.INVEST first appeared 2008-06-19, 1200z @ 21.2ºN 176.8ºE.


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86. reasonmclucus
6:12 PM GMT on June 19, 2008
Atmospheric scientists should stop focusing on the non-existent impact of carbon dioxide on climate and consider the impact of human actions that increase the amount of water vapor in the atmosphere. The combustion of hydrogen containing fuels adds water vapor to the air which in turn increases the amount of water available to fall as rain.

Increases in solar energy can also increase atmospheric water because as the oceans warm they evaporate more water.

Flood control efforts need to begin by recognizing that heavy rains/floods happen. In addition to draining of wetlands and paving of farmland for parking lots and large buildings, some flood control efforts may be increasing flooding. Upstream flood control efforts have often focused on getting rid of the excess of water as quickly as possible. For widespread rain events this approach increases downstream flooding because downstream areas have to handle their own rain as well as rain from upstream.

I wrote an essay on the subject after the flooding in the 90's and sent it to various government officials then. I have posted it at:

http://reasonmclucus.tripod.com/flood.html


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85. TampaSpin
2:29 PM EDT on June 19, 2008
Its about to tap into some moisture to its North also then things could change also.
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84. Drakoen
6:28 PM GMT on June 19, 2008
Member Since: October 28, 2006 Posts: 57 Comments: 29714
83. TampaSpin
2:27 PM EDT on June 19, 2008
It appears that the Atanlic wave might just make it into the Carribean with some energy still intack....then it could get interesting.
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82. guygee
6:23 PM GMT on June 19, 2008
75. atmoaggie 6:15 PM GMT on June 19, 2008
The IPCC is as impartial and objective as a state legislator whose "wife" owns a highway construction company.

Pushing their own agenda. The players stand to benefit in a more obvious way than the state legislator example.


atmoaggie - I am curious at to why you think a scientist pursuing a valid line of research that challenges the IPCC view would not receive an equal chance of funding?
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80. TampaSpin
2:25 PM EDT on June 19, 2008
Hey MLC wow been doing lawn work today...man is it humid.
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79. TampaSpin
2:22 PM EDT on June 19, 2008
68. jphurricane2006 1:40 PM EDT on June 19, 2008
well monkee due to the increase of cattle ranchers since man has made it on to earth, wouldnt there be more cows, chickens, horses, elephants, pigs, etc to create more methane??


Just a few weather blogs like this is all thats needed......LMAO
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78. Patrap
1:22 PM CDT on June 19, 2008
U.S. Geological Survey - science for a changing world
USGS Iowa Water Science Center
--

-- -- FLOOD INFORMATION -- USGS FLOOD RESOURCES -- JUNE FLOOD SUMMARY
Iowa Flood Information Page Link

Iowa State Webcams Link
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77. psualum95
2:20 PM EDT on June 19, 2008
-
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76. moonlightcowboy
1:18 PM CDT on June 19, 2008
75. Good reference and A M E N!
Member Since: July 9, 2006 Posts: 184 Comments: 29594
75. atmoaggie
6:11 PM GMT on June 19, 2008
The IPCC is as impartial and objective as a state legislator whose "wife" owns a highway construction company.

Pushing their own agenda. The players stand to benefit in a more obvious way than the state legislator example.
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74. HurakanPR
1:25 PM AST on June 19, 2008
Thanks Dr.Masters,Remarkable well documented information. And my respects to you, and all of the world wide respectful personalities, that are putting their grane of sand to save the emvironment. Of course including the prestigious north american gentleman ex-vicepresident, Mr.Gore.
73. Canesinlowplaces
6:04 PM GMT on June 19, 2008
Correction - that's www.petitionproject.org not .com.
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72. Canesinlowplaces
5:54 PM GMT on June 19, 2008
The IPCC based there gw findings on the work of 600 scientists. Then there were a few of them handpicked to actually make the final report. Most of the 600 had nothing to do with the final report and disagreed with it (i.e. humans are causing global warming). Go see the website www.petitionproject.com where you will find 31,000 scientists (of which 9,000 hold a phd) who say more or less that the IPCC findings are crap.
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71. moonlightcowboy
12:46 PM CDT on June 19, 2008
65. Oh, and let's not forget there's only about 6.5 billion homosapiens passing gas, too! Duh!
Member Since: July 9, 2006 Posts: 184 Comments: 29594
70. MonkeeInDaTrunk
10:41 AM PDT on June 19, 2008
68. jphurricane2006 10:40 AM PDT on June 19, 2008

well monkee due to the increase of cattle ranchers since man has made it on to earth, wouldnt there be more cows, chickens, horses, elephants, pigs, etc to create more methane??


hmmmm...someone needs to invent a device to attach to the rear ends of these animals, trap the fumes, and put them to good use....like fueling my car! Didn't CB invent some tunnels? Maybe he could come up with something....
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69. tillou
5:40 PM GMT on June 19, 2008
I think terms like "100 year flood" and "500 year flood" just like "100 year storm", relating to hurricanes, should not be used. I believe it gives the general public false security.

The "100 year flood" or how ever many year flood terms should be named something else. I have no idea what term should be used but it should be based on some type of percentage scale based on rain amounts in a given time period and drainage rates, etc.

The same goes towards "100 year storm" with hurricane surge. We should get rid of it all together and use a new term. Once again base it on the category of the storm, the shear size of it, forward speed, the elevations of the areas affected and the levees in the area.
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67. moonlightcowboy
12:39 PM CDT on June 19, 2008
65. Or crickets, mosquitoes? Uuuummmmm, how about insects? Good grief! Lame, lame, lame!
Member Since: July 9, 2006 Posts: 184 Comments: 29594
66. presslord
1:34 PM EDT on June 19, 2008
actually ...Gore's wealth...and the relatively sudden bump in it....comes from Google stock....
Member Since: August 13, 2007 Posts: 0 Comments: 10458
65. MonkeeInDaTrunk
10:37 AM PDT on June 19, 2008
but it's true....cow flatulance has been listed as one of the major contributing forces to "global warming"....what I want to know is, why just cows? Wouldn't an elephant let off more ozone busting fumes?
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63. MonkeeInDaTrunk
10:37 AM PDT on June 19, 2008
My bacon-double-cheeseburger is mighty tastey, thanks!

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61. TexasGurl
5:13 PM GMT on June 19, 2008
53.MonkeeInDaTrunk
"man-made" global warming....it's NOT man-made, it's "Clara-bell-the-cow-made"....animal flatulance is a major cause, don't ya know...


OMG!!! LOLOLOL
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59. tropicfreak
1:28 PM EDT on June 19, 2008


More flare ups of thunderstorms along the SE coast of FL and the bahamas.
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58. moonlightcowboy
12:23 PM CDT on June 19, 2008
Exactly, JP. One just has to follow the money trail to see what this is all about. And, it clearly funnels through Capital Hill.

If you don't believe me on this, P L E A S E just watch this short video that explains how ENRON was putting it to the people of California and this country and STILL IS! Oil demand causing price increases? Nah. A weak dollar causing price increases? Nah. Just watch the vid, then you'll know the entrenchment we're up against.

Link

This is staggering and makes me sick. A revolution of the people will be all that can resolve this! No statesman can get there to do something without being corrupted, bribed or blackmailed.

It's not about doing the "right thing!" It's about greed. The system is entrenched in corruption. And, it all goes through Capital Hill with lobby dollars! Washington is FOR SALE - all one has to do is send money! Bought a congressmen or a senator lately? They ain't cheap!


Member Since: July 9, 2006 Posts: 184 Comments: 29594
57. pearlandaggie
5:23 PM GMT on June 19, 2008
obviously, it's a pretty high fee
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55. OSUWXGUY
5:13 PM GMT on June 19, 2008
For those interested in following the MJO on a day to day basis, the animations at the following link are pretty helpful.

Link
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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.