With spring flooding already underway over portions of the U.S., NOAA forecasters are warning the worst is yet to come.
Almost half the country – from the North Central U.S. through the Midwest and the Northeast – has an above-average risk of flooding over the next few weeks, according to the annual spring outlook released last week by NOAA's National Weather Service.
The highest spring flood risk areas include the Red River of the North, which forms the state line between eastern North Dakota and northwest Minnesota, the Milk River in eastern Montana, the James and Big Sioux Rivers in South Dakota, the Minnesota River, the upper Mississippi River basin from Minneapolis southward to St. Louis, and a portion of lower New York, eastern Pennsylvania and northern New Jersey.
For Kansas, especially eastern Kansas, the greatest threat of floods along the Mississippi River come from disruption of downstream barge traffic moving grain to the Gulf of Mexico.
Many metropolitan areas have a greater than 95 percent chance of major flooding, including Fargo, Grand Forks, St. Paul, Davenport, Rock Island, Sioux Falls and Huron. Devils Lake in North Dakota has an 80 percent chance of reaching two feet above last year's record of 1452.1 feet.
Warm temperatures in the forecast this week could cause much of the snowpack to melt across South Dakota and southern Minnesota, setting off moderate to major flooding in eastern South Dakota next week. Minor flooding could begin this week on the Mississippi River and its tributaries over southeastern Minnesota and southwestern Wisconsin, leading to moderate to major flooding by early April.
National Weather Service models show this year's snowpack in the north-central U.S. contains a water content ranked among the highest of the last 60 years.