NOAA: Unprecedented spring flooding possible

Source: By Seth Borenstein and Jeff Martin, Associated Press • Posted: Monday, March 25, 2019

More than 200 million Americans are at risk for some kind of flooding, with 13 million of them at risk of major inundation, NOAA said in its spring weather outlook. About 41 million people are at risk of moderate flooding.

Major flooding now occurring in Nebraska, Iowa, South Dakota, Missouri and other Midwestern states is a preview of an all-too-wet and dangerous spring, said Mary Erickson, deputy director of the National Weather Service. “In fact, we expect the flooding to get worse and more widespread,” she said.

This year’s flooding “could be worse than anything we’ve seen in recent years, even worse than the historic floods of 1993 and 2011,” she said. Those floods caused billions of dollars in damage, and officials said this year’s damage in Nebraska, Iowa and South Dakota has already passed the billion-dollar mark.

Forecasters said the biggest risks include all three Mississippi River basins, the Red River of the North, the Great Lakes, plus the basins of the eastern Missouri River, lower Ohio River, lower Cumberland River and the Tennessee River.

“This is the broadest expanse of area in the United States that we’ve projected with an elevated risk that I can remember,” said Thomas Graziano, a 20-year weather service veteran and director of the Office of Water Prediction. “Is this the perfect storm? I don’t know.”

A lot depends on how much rain falls in the next couple of months, Graziano said, but forecasters say it will be more than average.

The Missouri River has already set records with historic flood marks measured in 30 places in Nebraska, Iowa and South Dakota, Kansas City forecaster Kevin Lao said.

It’s too early for scientists to make the complex calculations to see if human-caused climate change played a role in the flooding. However, scientists said the conditions are consistent with what they expect from global warming.

In addition to the year-to-year natural variability of weather, there is a long-term, climate-change-driven trend that is making extreme rainfalls even more intense, said Texas A&M University climate scientist Andrew Dessler.

“You can think of climate change as steroids for these rain events,” he said.

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