Near-Normal Flood Risk For Most Of Mississippi River Basin

Flood risk for most of the Mississippi River basin should be at or near normal averages for the next 90 days, according to officials of the National Water Center, except for the Ohio River and middle Tennessee River valleys, where it is elevated. To the north, the Red River of the North, which flows northward into Hudson Bay, is also expecting a higher flood risk. The National Water Center is a unit of the National Oceanic and Atmospheric Administration. 

The forecasts and assessments were given in the Spring Hydrologic Outlook for the Greater Mississippi River Basin in a webinar February 24. There were presentations on each of the sub-basins contributing to the Mississippi River.

This winter, temperatures have been colder than normal in the northern Plains and warmer than normal in the rest of the basin, according to NOAA hydrologist Katie Ertell. There is more water to release in the spring warm-up than last year at this time. Soil moisture is elevated across the Ohio and Tennessee River valleys, and river flows are much above normal in the Middle Mississippi and Ohio River valleys. The forecast is for minor to moderate flooding across eastern portions of the mid-Mississippi River basin, which is normal for this time of year. 

Jim Noel, a NOAA hydrologist, said he sees flood risk above normal for most of the Ohio River valley until May, when it will drop, but it is not as high as in 2018, 2011 or 1997. Major flooding is possible in Kentucky. As always, sudden severe rainstorms could change the outlook. 

Mike Welvaert, service coordination hydrologist at NOAA’s National Weather Service, reported that flood risk was normal across the Upper Mississippi River region except in the Red River, where it is increased. While some areas are getting increased rainfall, they are also recovering from a years-long drought. Some parts of the Upper Midwest have a frost depth of 1 to 3 feet, which could affect later spring flooding. 

In the Missouri River basin, Welvaert saw a reduced flood risk of between 10 percent and 30 percent compared to the 30-year averages, with a slightly increased risk in a small eastern area of the region. Mountain snowpack is below average. 

In the Arkansas River basin, most reservoirs and lakes are full, but the snow water equivalent in the upper basin is still below normal. Much of the basin is still recovering from significant drought, said senior hydrologist Lee Crowley. He rated flood risk as near normal but added that thunderstorms could determine future flooding. 

Soils are drier than normal in the Lower Mississippi River basin.