Red River rising: 18th consecutive year of flooding--why?

By: Dr. Jeff Masters , 3:08 PM GMT on March 19, 2010

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The Red River at Fargo, North Dakota continues to rise, with a peak expected Sunday at the 4th highest flood level observed in the past century. "Major" flood level is 30 feet, which the river surpassed on Wednesday, and the river is expected to crest near 38 feet on Sunday, just 2.8 feet below the record set last year. Flood stage is eighteen feet, and the Red River has now reached flood stage at Fargo for eighteen consecutive years, according to the U.S. Army Corps of Engineers. Prior to this remarkable stretch of flooding (which began in 1993), the river flooded in just 29 of 90 years. This year's flood is rated as somewhere between a 50-year and 100-year flood. Last year's record flood was a 100-year flood. The U.S. Army Corps of Engineers lists the 10-year flood level for the Red River at Fargo to be 10,300 cubic feet per second. A 10-year flood, historically, has a 10% chance of occurring in a given year. In the last twenty years, the Red River has had eight 10-year floods--one every 2.5 years, on average. This year is the fourth year out of the past five with a 10-year flood. Clearly, flooding has increased significantly along the Red River over the past twenty years.


Figure 1. Current and forecast flood stage for the Red River of the North at Fargo, ND. You can access images like these using our wundermap for Fargo with the "USGS River" layer turned on. Click on the icon for USGS station 05054000, then hit the "click for graph" link.

Reasons for flooding: landform factors
According the U.S. Geological Survey, the unique landform characteristics of the Red River Valley make it highly susceptible to flooding. These factors include:

1) A relatively shallow and meandering river channel--a shallow channel holds less water and the meandering can cause flow to slow down as the channel makes its turns, causing over-bank flooding.

2) A gentle slope (averaging 0.5 to 1.5 feet per mile) that inhibits channel flow and encourages overland flooding or water "ponding" (especially on even, saturated ground) in the basin.

3) The northerly direction of flow--flow in the Red River travels from south (upstream) to north (downstream). The direction of flow becomes a critical factor in the spring when the southern (upstream) part of the Red River has thawed and the northern (downstream) part of the channel is still frozen. As water moves north toward the still frozen river channel, ice jams and substantial backwater flow and flooding can occur.


Figure 2. Peak flow of the Red River at Fargo, North Dakota through time. The two largest flow rates occurred last year (2009), and in 1997. The projected crest for Sunday (red circle) would be fourth greatest flood since reliable records began in 1901. Image credit: U.S. Geological Survey.

Reasons for this year's flood: highly unfavorable weather conditions
The USGS also cites five weather factors that can act to enhance flooding along the Red River. All five of these factors occurred to a significant degree this year:

1) Above-normal amounts of precipitation in the fall of the year that produce high levels of soil moisture, particularly in flat surface areas, in the basin. North Dakota had its 22nd wettest fall in the 115-year record in 2009.

2) Freezing of saturated ground in late fall or early winter, before significant snowfall occurs, that produces a hard, deep frost that limits infiltration of runoff during snowmelt. Fargo had a November that was much warmer than average, followed by a sudden plunge to below-zero temperatures by the second week of December. This froze the saturated ground to a great depth.

3) Above-normal winter snowfall in the basin. North Dakota had a top 15% winter for precipitation, with the period December 2009 - February 2010 ranking 15th wettest in the past 115 years.

4) Above-normal precipitation during snowmelt. Precipitation for March 1 - 18 has been 1.41", compared to the average of 0.61".

5) Above-normal temperatures during snowmelt. High temperatures in Fargo have averaged 6°F warmer than normal for March 1 - 18.

Urbanization increases flooding
Urbanization has had a major impact on increasing flooding not only along the Red River, but in every river basin in the U.S. Many cities and developed areas are located in flood plains next to major rivers and their tributaries. Highways, streets, parking lots, sidewalks, and buildings now cover large areas of the ground that used to absorb excess rain water and slow the rate at which run-off from precipitation and melting snow reached rivers. By developing large portions of our flood plains, run-off now reaches rivers more quickly, generating higher floods.

Building levees and flood defenses increases flood peaks
Defending ourselves against floods has made floods worse. Every time a new levee is built, or an old floodwall raised in height to prevent overtopping, more and more water is forced into the river bed, which raises the height of the flood. Flood waters that used to be able to spread out over their natural flood plains are now forbidden from spilling out over newly developed land in flood plains. For example, proposed improvements to the flood defense system in Fargo could cause a 4 - 10 inch rise in floods immediately downstream from the city, according to the Army Corps of Engineers.

Precipitation is increasing
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. Satellite measurements (Trenberth et al., 2005) have shown a 1.3% per decade increase in water vapor over the global oceans since 1988. Santer et al. (2007) used a climate model to study the relative contribution of natural and human-caused effects on increasing water vapor, and concluded that this increase was "primarily due to human-caused increases in greenhouse gases". This was also the conclusion of Willet et al. (2007). This increase in water vapor has very likely led to an increase in global precipitation. For instance, 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). Precipitation over the Red River drainage basin increased by about 10 - 20% during the 20th Century (Figure 3.) 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. These are the type of events most likely to cause flooding. 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.


Figure 3. Change in precipitation over the U.S. between 1900 - 2000, from the U.S. Cooperative network. Precipitation in the Red River drainage area increased by 10 - 20% over the 20th century. Image credit: Contemporary Changes of the Hydrological Cycle over the Contiguous United States: Trends (Groisman et al., 2002).

The future of flooding
As the population continues to expand, development in flood plains and construction of new levees and flood protection systems will continue to push floods to higher heights. With global warming expected to continue and drive ever higher precipitation amounts--falling preferentially in heavy precipitation events--it is highly probable that flooding in the Red River Valley--and over most of the northern 2/3 of the U.S. where precipitation increases are likely--will see higher and more frequent floods. With these higher and more frequent floods comes the increased risk of multi-billion dollar disasters, when a record flood event overwhelms flood defenses and inundates huge areas of developed flood plains. Obviously, we need to make smart decisions to limit development in flood plains to reduce the cost and suffering of these future flooding disasters.

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.

Milly, P.C.D., R.T. Wetherald, K.A. Dunne, and T.L.Delworth, Increasing risk of great floods in a changing climate", Nature 415, 514-517 (31 January 2002) | doi:10.1038/415514a.

Santer, B.D., C. Mears, F. J. Wentz, K. E. Taylor, P. J. Gleckler, T. M. L. Wigley, T. P. Barnett, J. S. Boyle, W. Brüggemann, N. P. Gillett, S. A. Klein, G. A. Meehl, T. Nozawa, D. W. Pierce, P. A. Stott, W. M. Washington, and M. F. Wehner, 2007, "Identification of human-induced changes in atmospheric moisture content", PNAS 2007 104: 15248-15253.

Trenberth, K.E., J. Fasullo, and L. Smith, 2005: "Trends and variability in column-integrated atmospheric water vapor", Climate Dynamics 24, 741-758.

Willett, K.M., N.P. Gillett, P.D. Jones, and P.W. Thorne, 2007, "Attribution of observed surface humidity changes to human influence", Nature 449, 710-712 (11 October 2007) | doi:10.1038/nature06207.

Links
A good way to track the flooding event is to use our wundermap for the Red River with the USGS River layer turned on.

The Fargo Flood webpage of North Dakota State University, Fargo, has some excellent links.

I'll have a new post on Monday or Tuesday.

Jeff Masters

Red River Flood 2006 (mw25)
The water level of the Red River when I took this photo was 47.2 feet, 19.2 feet above flood stage and the 6th highest level in Grand Forks' history. The river is expected to crest at 47.4 feet on Wednesday morning. Luckily, no homes have been lost in the Grand Forks area as of yet due to the flooding.
Red River Flood 2006
Fargo Flood 2009 - Elm & 15th Ave. N. (tliebenow)
Picture says it all. Clay dike built to contain the Red River in North Fargo.
Fargo Flood 2009 - Elm & 15th Ave. N.

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Good Morning everybody! Well after a start at 37F this morning, we're headed up to 68F.

That's alot better than the 30's and snow of Saturday evening!!
Member Since: August 25, 2009 Posts: 20 Comments: 6785
1009. IKE
Quoting severstorm:
Morning Ike, I just thought i would let you know i did my part for GW. I burned for 6 hrs yesterday and my yard looks great now. LOL


LOL...congrats!
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Morning Ike, I just thought i would let you know i did my part for GW. I burned for 6 hrs yesterday and my yard looks great now. LOL
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RE: 989

I live in that snow area. We got six inches Friday night. Its nothing out of the ordinary tho, we're at 7200 ft. Springtime in the Rocky Mtns.
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A VERY SAD DAY TO BE AN AMERICAN THIS MORNING!! Having the government take over student loans and force you to get loans from them only! Government make you buy insurance! Those are not principles that this country were founded on! This is the beginning of the government taking away our rights!

beyond that had some nasty storms yesterday in Melbourne,Fl but nothing to severe.
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And we are still not hitting normal temps here in the Bay Area.....


By Bay News 9 meteorologist Brian McClure

Spring is officially here and the final numbers are in on the very long, cold winter we had.

At the Tampa International Airport the average temperature for the winter was only 56.2 degrees. This will go down as the second coldest winter ever on record at the Tampa International Airport (coldest year was 1978 when the average temperature was 55.6 degrees).

In Saint Petersburg the average temperature for the winter was only 56.9 degrees. This is officially the coldest winter ever on record for Saint Petersburg.
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996. xcool
BahaHurican thank
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Interesting surface temps map, xcool.
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Yup.... puddle was already there when the rain held up. Wonder if that's it for the rest of the night, or if round 2 is coming up...

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993. xcool





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Looks like Grand Bahama and Abaco are getting the worst of it...

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Woke up just as the downpour started here... Some thunder, fairly heavy rain. Think I'm going to move my car so it's not sitting in a big puddle when I'm ready to go to work....
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Snow coming!
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Look at this snow....YOu gotta be kidding, it's mid March.
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Cooler days coming south again.
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Quoting Patrap:
Well TS,..as one who just had Presslord and with his wife,along with the Christopher Reeve Foundation here to visit you can ask Him How I live friend.
But as Relief and Communications Coordinator for Portlight,..I'd reconsider your approach to communicating here on that level.

But we thank you for supporting us on your other site...

tampaspinsweather.webs.com

G'night.




Nice how PatRap brings up PortLight with his Political beliefs. I doubt as hard as Paul Timmons works he appreciated that. Paul might want to consider his position in PortLight as that was totally uncalled for. PortLight does not deserve this kind of PR that Pat just did.

Where does my political Beliefs and our work come up Sports Fan,LOL

But your comment speaks Volumes as a Man of 50.
I have a Daughter in College,and a Son in Jesuit High here as well..

So your insulting quip denotes your intent and demeanor.

975. TampaSpin 12:20 AM CDT on March 22, 2010

As an Independent that you claim, A cave you must live as you speak......LMAO!


You are Quite a spinner as your handle Implies ..LOL

Have fun.


As you always are the police officer on this blog and direct people to take there Political beliefs out of here.....what did you just do..WHATEVER!
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986. xcool
:) that good .
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Quoting xcool:
TampaSpin "it's good seeing you


Yep its a shame that some have to ruin a blog and sorry if i offended anyone. PatRap as usual started his insults as all can see. Sorry!
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983. xcool
TampaSpin "it's good seeing you
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Quoting xcool:
hey TampaSpin ;)


Hey my friend!
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981. xcool
hey TampaSpin ;)
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Quoting SouthALWX:


c'mon now Pat... His arguments with you as an individual have no bearings on his alignment with Portlight. I assume Portlight has no political preference or was I mistaken? (I hope not)And TS, no reason to be so forward here. Disagree and move on please :)


Nice how PatRap brings up PortLight with his Political beliefs. I doubt as hard as Paul Timmons works he appreciated that. Paul might want to consider his position in PortLight as that was totally uncalled for. PortLight does not deserve this kind of PR that Pat just did.
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978. xcool
i justing add pat to my facebook friend list haha
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Quoting washingaway:


I knew that was coming! Just surprised it took so long.

Quoting Patrap:
Well TS,..as one who just had Presslord and with his wife,along with the Christopher Reeve Foundation here to visit you can ask Him How I live friend.
But as Relief and Communications Coordinator for Portlight,..I'd reconsider your approach to communicating here on that level.

But we thank you for supporting us on your other site...

tampaspinsweather.webs.com

G'night.

c'mon now Pat... His arguments with you as an individual have no bearings on his alignment with Portlight. I assume Portlight has no political preference or was I mistaken? (I hope not)And TS, no reason to be so forward here. Disagree and move on please :)
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Quoting Patrap:
Someone may want to check their Header spelling as its Democrat's,..not "Democarts"..

A Lady from Minnesota made a similar mistake today too.

#
Michele Bachmann - "Amaricas" Congress Woman
Official site for Rep. Michele Bachmann, who was elected to represent Minnesota's Sixth Congressional District in 2006.
www.michelebachmann.com - Cached

As a "Independent" weary one,..I head Upstairs now to the WUnderland Cave,..


As an Independent that you claim, A cave you must live as you speak......LMAO!
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NICELY WELCOMED! Watch what happens tomorrow!

U.S. Stock Futures

Data as of 12:34am ET

S&P -10.70 / -0.92%

Nasdaq -19.00 / -0.98%

Dow -92.00 / -0.86%
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972. HadesGodWyvern (Mod)
Japan Meteorological Agency
Tropical Disturbance Summary
TROPICAL DEPRESSION XX
9:00 AM JST March 22 2010
=============================

At 0:00 AM UTC, Tropical Depression (1006 hPa) located at 7.0N 144.0E has 10 minute sustained winds of 25 knots with gusts of 40 knots. The depression is reported as moving west northwest slowly.
Member Since: May 24, 2006 Posts: 50 Comments: 45235
971. emguy
964...Thanks for sharing. I really didn't realize just how crazy Ted Kennedy was until I saw his eyes in this picture...and I didn't realize how crazy things were until I heard all those "eyes" on the House floor tonight. Yes you can, but should you?

Just trying to have some good humor folks...don't sweat it, okay? We all need a laugh sometimes.
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OK COOK!.......LMAO
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Quoting Patrap:
Well at least the stock quotes have trailed off..LOL


and you got a pretty nice avatar.
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Quoting TampaSpin:


Take your Political CRAP somewhere else as you have said MANY TIMES!


I knew that was coming! Just surprised it took so long.
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Quoting Patrap:
.."For me, this is a season of hope, new hope for a justice and fair prosperity for the many and not just for the few, new hope. And this is the cause of my life, new hope that we will break the old gridlock and guarantee that every American -- north, south, east, west, young, old -- will have decent, quality health care as a fundamental right and not a privilege"..



Take your Political CRAP somewhere else as you have said MANY TIMES!
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963. xcool
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FEMA: Hurricane Preparation 2010
Member Since: July 3, 2005 Posts: 423 Comments: 127874
Quoting all4hurricanes:

Polo?

First TS (soon) of the northern hemesphere
Good night everyone


LMAO Have a Good Evening Too....

:0)
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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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