The combination of April deluges in the lower and mid-Mississippi river valley and melt from near-record winter snows farther upstream is leading to historic flooding of America’s largest river. In Memphis, the Mississippi is expected to crest around 48 feet next Wednesday, the second highest level on record. 2,832 properties may be impacted and officials are telling residents to evacuate nearly 1,000 homes vulnerable to inundation.
Yesterday, the mighty river broke through a temporary levee in Memphis, submerging a downtown airport.
The 48 foot crest expected May 10 in Memphis would be second to only the great flood of 1937 when the river rose to 48.7 feet. And there is further trouble expected downstream. Jeff Masters at Wunderground writes:
...flood waters pouring in from the Arkansas River, Yazoo River, and other tributaries are expected to swell the Mississippi high enough to beat the all-time record at Vicksburg, Mississippi by 1.3’ on May 20, and smash the all-time record at Natchez, Mississippi by six feet on May 22, and by 3.2 feet at Red River Landing on May 23. Red River Landing is the site of the Old River Control Structure, the Army Corps’ massive engineering structure that keeps the Mississippi River from carving a new path to the Gulf of Mexico. ... Its failure would be a serious blow to the U.S. economy, and the great Mississippi flood of 2011 will give the Old River Control Structure its most severe test ever. Also of concern is the forecast for the Mississippi to crest at 19.5 feet in New Orleans on May 24. The levees in New Orleans protect the city for a flood of 20.0 feet--that is not much breathing room.
Headed back upstream, flood waters are receding where the Ohio River and Missippi intersect - the same location where the U.S. Army Corps of Engineers had to blow up a levee to save the town of Cairo, Il.
Our Amazing Planet reports on the outcome of the levee destruction:
The plan seems to have worked. Water at the point where the Ohio River meets the Mississippi has dropped 1.7 feet (0.5 meters) since the blasting, down from a record 61.72 feet (19 m)
Aside from the record in Cairo, two other locations along the Mississippi and its tributaries established new crest records: Caruthersivlle, Mo. and Pocahontas, Ar. (along the Black River).
The extraordinary flooding that has occurred in the middle part of the country is not entirely unexpected. In its spring outlook, the National Weather Service highlighted the potential for “record flooding” in the North Central U.S. As it turns out, the extreme flooding has occurred just south of that projection coinciding with the heaviest rains. For example, Memphis has received 11” of rain since April 25.