Mississippi River flood of 2011 already a $2 billion disaster

The Mississippi River continues to rise to heights never seen before along its course through the states of Mississippi and Louisiana. At Natchez, Mississippi, the river has already hit 59 feet, breaking the previous all-time record of 58 feet set in the great 1937 flood. The river is expected to keep rising at Natchez until May 21, when a crest of 64 feet--a full six feet above the previous all-time record--is expected. Record crests are also expected downstream from Natchez, at Red River Landing and Baton Rouge, Louisiana, on May 22. Fortunately, the levee system on the Lower Mississippi constructed by the Army Corps of Engineers is built to withstand a greater than 1-in-500 year flood, and this flood is "only" a 1-in-100 to 1-in-300 year flood. However, flooding on tributaries feeding into the Mississippi is severe in many locations along the Mississippi, since the tremendous volume of water confined behind the levees is backing up into the tributaries. Huge quantities of farmland are being submerged in the great flood, and damages already exceed $2 billion. Rainfall amounts of at most 1.25 inches are expected over the Lower Mississippi River watershed over the next five days, which should prevent flood heights from rising above the current forecast.


Figure 1. A crowd of hundreds gathered to watch Monday as the Army Corps of Engineers opened gates on the Bonnet Carre' Spillway to allow flood waters from the Mississippi River to flow into Lake Pontchartrain. Image credit: Army Corps of Engineers.

Damage from flood over $2 billion, could hit $4 billion
Damage from the Mississippi River flood of 2011 is already over $2 billion, and could surpass $4 billion. Among the damages so far, as reported by various media sources:

$500 million to agriculture in Arkansas
$320 million in damage to Memphis, Tennessee
$800 million to agriculture in Mississippi
$317 million to agriculture and property in Missouri's Birds Point-New Madrid Spillway
$80 million for the first 30 days of flood fighting efforts in Louisiana

The Mississippi River flood of 2011 now ranks as the 10th costliest flooding disaster in the U.S. since 1980, according to The National Climatic Data Center Billion Dollar Weather Disasters list. The top ten most expensive U.S. flood disasters since 1980 are:

1) $30.2 billion, Summer 1993 Upper Mississippi and Midwest flooding
2) $15.0 billion, June 2008 Midwest flooding
3) $7.5 billion, May 1995 TX/OK/LA/MS flooding
4) $4.8 billion, 1997 North Dakota Red River flood
5) $4.1 billion, Winter 1995 California flooding
6) $4.0 billion, January 1996 Mid-Atlantic and Northeast, blizzard rain and snow melt flooding
7) $3.9 billion, Winter 1996 - 1997 West Coast flooding
8) $2.3 billion, Winter 1982 - 1983 El Niño-related West Coast flooding
9) $2.3 billion, May 2010 Tennessee flood
10) $2 billion, May 2011 Mississippi River flood

With the Morganza Spillway, 35 miles upstream from Baton Rouge, likely to be opened sometime between Friday and Tuesday, hundreds of millions more in damage will occur along the Atchafalaya River basin, which will take up to 300,000 cubic feet per second of water out of the Mississippi and funnel it down to the Gulf of Mexico. About 22,500 people and 11,000 structures will be affected by some flooding, according to Governor Jindal of Louisiana. Also of concern is the impact all the fresh water flows from planned diversions of the Mississippi into salt water oyster beds. According to nola.com, fresh water kills oysters because it wreaks havoc on their metabolism, preventing them from keeping a saltwater balance. Increased fresh water diversions in 2010, used to keep the Deepwater Horizon oil spill away from the coast, contributed to a 50% drop in oyster harvests in 2010 compared to 2009. The huge flow of fertilizer-laden fresh water into the Gulf of Mexico is also expected to create a record-size low-oxygen "dead zone" along the coasts of Louisiana and Texas. This year's dead zone could be as much as 20 percent greater than the record set in 2002, said Louisiana State University marine biologist Eugene Turner in an article published by nola.com. That year, the low oxygen area stretched over 8,500 square miles, an area the size of New Jersey. Dead zones are due to low oxygen level caused by blooms of algae that feed off all the fertilizers washed off of the farms in the Midwest by the Mississippi River.

A record number of billion-dollar weather disasters for so early in the year
The U.S. has already had five weather disasters costing more than a billion dollars this year, which has set a record for the most number of such disasters so early in the year. We've already beat the total for billion-dollar weather disaster for all of 2010 (three), and with hurricane season still to come, this year has a chance of beating 2008's record of nine such disasters. The billion dollar weather disasters of 2011 so far:

1) 2011 Groundhog Day's blizzard ($1 - $4 billion)
2) April 3 -5 Southeast U.S. severe weather outbreak ($2 billion)
3) April 8 - 11 severe weather outbreak ($2.25 billion)
4) April 25 - 28 super tornado outbreak ($3.7 - $5.5 billion)
5) Mississippi River flood of 2011 ($2+ billion)

Losses from the on-going Texas drought and wildfires are already at $180 million, and this is likely to be a billion-dollar disaster by the time all the agricultural losses are tallied.

Good links to follow the flood:
Summary forecast of all crests on Lower Mississippi and Ohio Rivers.
Wundermap for Vicksburg, MS with USGS River overlay turned on.
National Weather Service "May 2011 Mississippi River Flood" web page

Jeff Masters