Davenport Flooding 2019: Mississippi River floods downtown Davenport
A flood dam broke on April 30, 2019, allowing Mississippi River waters to spill into downtown Davenport.
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The flooding that broke levees, inundated farms and inundated homes and businesses in cities and towns across Iowa, Nebraska and other Midwestern states two years ago is part of a climate change-driven weather phenomenon that, according to scientists happens more often.
A new University of Iowa study says rising greenhouse gas concentrations caused by human activity are causing an increased frequency of a weather phenomenon researchers call the “Midwest waterspout.”
The Midwest water plume pulls moisture from the Gulf of Mexico that then rises above cold dry air from the North, leading to heavy rain in the Midwest. The weather phenomenon has been occurring more frequently in the past 40 years, researchers Wei Zhang and Gabriele Villarini wrote in a newly published study.
In 2019, the Midwest Water Pipe combined with melting snow drove the Missouri and Mississippi rivers beyond their banks, causing widespread damage. Flooding across the Midwest caused about $6.3 billion in damage before it ended, according to the National Oceanic and Atmospheric Administration.
Researchers say the Midwest waterspout contributed about 70% of total Midwest precipitation in 2019, more than double the historical average. Nationally, 2019 was the second-wettest year on record, averaging 34.78 inches, behind only 1973, NOAA said.
MORE: Flooding has hit every Iowa county since 1988, some as many as 17 times
Using climate models, Zhang and Villarini determined that natural climate fluctuations could not explain the increased frequency of “Midwest Waterspout” events. But when they accounted for increasing concentrations of greenhouse gases caused by human activity, they could replicate the observed increases.
Researchers say Iowa and the central US will be more prone to frequent and severe flooding if greenhouse gas emissions are not reduced. “We would expect what we're experiencing to become more the norm, rather than the exception,” said Villarini, director of the University of Iowa's IIHR-Hydroscience & Engineering.
The historic floods of 2019 shut down cities and kept thousands of families out of homes and workers out of businesses for weeks. It hit small towns like Hamburg and Pacific Junction as well as large cities that included Davenport.
About a third of Offutt Air Force Base, outside Omaha, Nebraska, was underwater.
Climate scientists have warned that the Midwest will see more extreme weather events, from increased heavy spring rains to summer droughts.
The research was published in this month's Philosophical Transactions of the Royal Society, Mathematical, Physical, and Engineering Sciences.
Zhang, who was at the University of Iowa, is now an assistant professor at the University of Utah.
Donnelle Eller covers agriculture, environment and energy for the Register. Contact her at deller@registermedia.com or 515-284-8457.
