State Climatologist Justin Glisan says most infrastructure like levies and storm sewers is not built for the type of torrential rain and flooding that’s occurring.
“You look at 2019 with the ‘bomb cyclone’ and then the epic flooding along the Missouri River basin, all the Corps levies south of Council Bluffs were damaged or destroyed. Those have since been rebuilt,” Glisan said during a recent appearance on “Iowa Press” on Iowa PBS.
Glisan said urban infrastructure can’t keep up with “high intensity” rainfall. “Instead of getting these historic quarter inch, half an inch over 24-48 hours, you’re getting an inch to three inches,” Glisan said. “Our systems can’t keep up with that type of behavior and we’re only seeing that behavior increase into the future.”
Forecasts indicate there will be a 10-15% increase in precipitation in Iowa over the next 10 to 15 years and Glisan said that will sadly lead to more flooding.
As for the other severe weather that’s hit the state this spring, Glisan said mobile radars deployed during the Greenfield tornado may help improve forecasting tornadoes.
“The science that we’re going to get out of it I really think is going to move us forward in terms of advanced lead times,” Glisan said. “and even predicting these types of tornadoes further out.”
As Radio Iowa reported last month, the preliminary data from the Greenfield tornado includes a measurement that wind speeds were 318 miles per hour at 160 feet above the ground. That means the Greenfield tornado was the second strongest tornado ever recorded.
“It’s hard to fathom,” Glisan said.
