Hard to Predict Iowa Floods?

Hard to predict Iowa rivers' flood odds, experts say
By Adam Belz
The Gazetteadam.belz@gazettecommunications.com
Worth A Look
LINKS OF INTEREST
National Weather Service Rivers and Streams
National Weather Service Advanced Hydrologic Prediction Service
National Oceanic and Atmospheric Administration Climate Attribution (including explanation of 2008 flood)
United States Geological Survey Real-Time Water Data
IOWA CITY - Chances that the Cedar or Iowa River will flood again this spring are slightly below average.But Midwestern weather has grown steadily more volatile over the past century, and if one thing is certain about flood forecasting, it's that it is not certain.How much it snows before spring, and then how much it rains, may change all the predictions.But considering the information available now — soil saturation last fall, depth of winter hard frost and the amount of snow on the ground — the likelihood of a flood is not high.That's in contrast to last year, when "the gun was cocked pretty good," said Steve Buan, of the National Weather Service's North Central River Forecast Center in Minneapolis.Buan was among the 30 or so experts on weather, climate, rivers and emergency management gathered at the University of Iowa on Wednesday to discuss climate change, flood predictions and government response to floods. The experts came from the National Weather Service, the University of Iowa, Iowa State University, the U.S. Geological Survey, the National Oceanic and Atmospheric Administration, Linn County and the Iowa Department of Homeland Security.Last June's flood illustrates the difficulty of accurate long-term predictions.Though the ground was saturated through early June, and chances of flooding were above average, none of the computer models predicted a major flood in early June — because none of the models predicted 12 inches of rain between May 15 and June 15."Our ability to forecast rainfall is pretty good a day or two in advance," said Ray Wolf, a science and operations officer at the National Weather Service in the Quad Cities.Beyond two days, it's spotty.Those 12 inches of rain over the Cedar River watershed in June triggered flash floods just as the river was cresting. The probability of such heavy rainfall in that period was one in 1,000, said Chris Anderson, assistant director of the Climate Science Initiative at Iowa State University."I don't think we've done the research to eliminate bad luck," he said.Eugene Takle, director of the Climate Science Initiative at Iowa State, projects with limited confidence that Iowa is entering an era of higher annual precipitation, more severe rainfall, though it may be sporadic, and more rapid flooding.He said annual precipitation in Cedar Rapids has risen by 30 percent since 1896, from about 28 inches per year to 37 inches per year.So the stakes, if anything, have been raised. The larger question Wednesday, with the Iowa River churning in the background under the Burlington Street bridge, was how these experts can translate their research into usable information for the public.Shripad Deo, a sociologist and researcher with the Cooperative Institute for Research in the Atmosphere, said all agencies need to better gear their research toward practical applications."There is a list of information that is provided, but it's not usable," said Deo, who is one of dozens of scientists working at the institute, a joint effort of NOAA and Colorado State University.Anderson, the ISU scientist, said that's is a difficult problem for federal agencies like NOAA. But he said he would put together a report for NOAA after the two-day conference in Iowa City, adding he thinks the agency could cooperate with local emergency management agencies or university extension services to better communicate with the public.He also said inundation maps — the kind that show who will get flooded at which river levels — are an important project. Cedar Rapids officials are already working on such a map.But these projects and improved Web sites take time and resources."That's the problem that these federal agencies are facing," Deo said. "They're not trained to explain."