[link to www.nytimes.com (secure)] 25 States Are at Risk of Serious Flooding This Spring, U.S. Forecast Says (John Schwartz does good work there)

Nearly two-thirds of the lower 48 states will have an elevated risk of some flooding from now until May, and 25 states could experience “major or moderate flooding,” according to the National Oceanic and Atmospheric Administration.

“The flooding this year could be worse than anything we’ve seen in recent years, even worse than the historic floods of 1993 and 2011,” said Mary C. Erickson, deputy director of the National Weather Service, in a conference call with reporters. The major flooding this month in Nebraska, Minnesota, Iowa and elsewhere is “a preview of what we expect throughout the rest of the spring,” she said.

Some 13 million people could be exposed to major flooding, making this a “potentially unprecedented” flood season, said Edward Clark, director of NOAA’s National Water Center.

The agency’s scientists also predicted that the chemical runoff from the rains would cause above-average hypoxia conditions — “dead zones” of water with low oxygen caused by nutrient pollution that can kill fish and other marine life — in the Gulf of Mexico and Chesapeake Bay.

More rainfall in the Midwest is a predictable consequence of climate change, according to the most recent National Climate Assessment, which was produced last year by 13 federal agencies. A warmer atmosphere can hold more moisture, which comes down as precipitation.

The current flooding in the Missouri River basin and beyond has been caused in part by heavy rains, but has been further complicated by other factors, like frozen ground that kept water from being absorbed.