Waters to rise, flooding to last weeks on lower Mississippi River
Surging river levels brought on by days of rain in early April will lead to flooding for weeks from the Ohio confluence to where it drains into the Gulf.
AccuWeather’s flooding expert Alex Sosnowski was live on the AccuWeather Network on April 11 to discuss flooding in the southeastern and north-central U.S.
A slow-moving flood event is just getting underway for the lower portion of the Mississippi River and will last until nearly the end of the month in some places, following the early April deluge that spanned a large area of the river basin.
Because of its massive size and meandering nature over relatively flat terrain, it takes many days to weeks for water to travel from the confluence of the Ohio River to the mouth of the Mississippi River at the Gulf. This is why the flood cycle can take a month to complete on the lower Mississippi River.
As water levels rise above the river's normal banks, it spills into unprotected communities and farmland, where it can remain for many days or a few weeks because of the flat terrain that drains poorly. Even after the waters recede, it can take many more days before agricultural fields can be worked, depending on drying conditions.
As waters over the Ohio River receded last week, waters will surge farther downstream on the Mississippi River. Levees will be tested. Some roads and bridge access points will be closed for many days. Communities that are not protected by levees will face high water for an extended period.
For example, on the Mississippi River at Osceola, Arkansas, a crest occurred this past week—well above the major flood stage closing in on 38 feet. It may take until early this week before levels drop below major flood stage.
Farther downstream, at Vicksburg, Mississippi, the river is not expected to crest until around April 26 and may not fall within its normal banks until early May, depending on local and upstream rainfall in the days ahead.
Meanwhile, hundreds of miles downstream, as the crow flies, from the Ohio River confluence at Baton Rouge, Louisiana, the Mississippi is not projected to crest at major flood stage until the last week of April.
It will be well into May before the river returns to its normal banks throughout its watershed, assuming no additional heavy rain events occur along the massive system.
The major, usually inexpensive means of transporting goods, grains and raw materials will face some obstacles. The high levels on the Mississippi River, combined with a faster-than-average flow and perhaps even less clearance beneath some of the bridges, will force tugboats to push fewer or fewer full barges up and downstream. Some of the ports along the river below St. Louis may be closed due to high water.
While the pattern looks to be progressive and not conducive to renewed flooding on the magnitude and extent of early April, there can be an outbreak of severe weather and tornadoes with renewed flooding at the local level or possibly flooding in areas that were unaffected a week ago.
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