With above-average precipitation across many of the lower 48 states, the National Oceanic and Atmospheric Administration (NOAA) is already warning many of these states of the potential for spring flooding. According to the NOAA, nearly two-thirds of the United States will be under elevated flood risk through May.
The highest risk areas for moderate to major flooding including the upper, middle and lower Mississippi River basins. This includes the mainstem Mississippi River, Red River, and North, Great Lakes, eastern Missouri River, lower Ohio River, lower Cumberland River, and Tennessee River basis.
The large area of the U.S. east of the Mississippi River and in portions of California, the Pacific Northwest and the Great Basin are also being warned of the possibility of minor flooding events.
There are many reasons the NOAA is heeding such harsh warnings early on. The near-record snowpack left in early March, heavy rain, ice jams and, frozen ground has already brought rivers in the Plains and Midwest to record levels. With more moisture than normal, combined with snow still melting – the flooding is expected to expand.
The upper Mississippi and Missouri basins in Iowa, Minnesota, and Nebraska have already breached. Excess water from all of these factors will flow downstream – causing moderate to major flooding throughout many parts of the country.
Ed Clark, director of NOAA’s National Water Center in Tuscaloosa, Alabama said, “This is shaping up to be a potentially unprecedented flood season,” followed by “The extensive flooding we’ve seen int he past two weeks will continue through May and become more dire and may be exacerbated in the coming weeks as the water flows downstream.”
The NOAA considers various factors in the flood outlook predictions such as current snowpack, drought, soil moisture, streamflow, frost depth, and precipitation. Along with spring also comes heavy local rains which can lead to flooding not currently in the outlook as well.
One area that is happy about the heavier precipitation this year is California. They have been knocked out of the years-long drought thanks to the extra precipitation this year.
