Mississippi Basin Flood Outlook Shows Little Change

The National Weather Service issued an updated flood outlook for the Mississippi River basin and its sub-basins March 10 that showed little change from its previous flood outlook estimate. The team forecast normal to near-normal flood risk for most of the Mississippi River Basin, with elevated flood risk along the Ohio River valley and some of its tributaries, along with parts of the Upper Mississippi River, and drier than normal conditions in the Missouri River basin.

As always, the team cautioned that local heavy rains or storms could cause localized flooding at any time.

The NWS team said the Missouri River basin continues to experience “widespread persistent drought across most of the Great Plains into Montana and Wyoming.” There is less than an inch of snow water across Kansas, Nebraska, South Dakota and most of Montana, eastern Wyoming and eastern Colorado.

Jim Noel, a service coordination hydrologist at NWS, reported slightly above- normal rainfalls along the Cumberland River basin. He expects minor to moderate flooding by early May in some of its tributaries, with a 25 percent or greater chance of elevated flood risk.

Pool levels are elevated in the Ohio River basin due to recent rain events, Noel said. The Corps will be draining them down over the next couple of weeks, but there’s “plenty of flex storage.” He rated flood risk above normal in Ohio, eastern Illinois and Kentucky.

The NWS’ Mike Welvaert noted a few significant storms in the Upper Plains, with warm weather causing rapid snowmelt that added to the rain and caused ice breakups and moderate flooding. The Red River of the north, which drains into Hudson Bay, continues to be an area of flooding concern, he said. The highest water content is in soils in northern Minnesota, northern Michigan and North Dakota; he said there is an average risk for widespread significant flooding in the region, with above-average risk for the Red River valley and a chance for major flooding in the Upper Mississippi River. Future rainfalls and how quickly the frozen rivers and soils warm up will be the main driver for future flood risk, he said.

“Minor flooding is likely at almost all forecast points along the Mississippi in the St. Louis service area, near historical norms,” the NWS said.