On Thursday, the National Weather Service (NWS) released it river flooding forecasts for spring. According to the NWS Advanced Hydrological Prediction Service, Iowa City shouldn’t see any river flooding during that period, but puts chances that the Cedar River will surge past flood levels in Cedar Rapids this spring at 25 to 50 percent.
Flood stage for the Iowa River in Iowa City starts at 23.5 feet, and at 12 feet for the Cedar River in Cedar Rapids, according to the NWS.
The NWS predicts a 25 to 50 percent chance of the Cedar River in Cedar Rapids reaching minor flooding levels (up to two feet above flood level) for three weeks, starting during the week of March 11. The worst case scenario according to the new analysis is for the city to experience moderate flooding (two to four feet above flood level) during those three weeks, followed by two weeks of minor flooding. In this scenario, after a week without any flooding, Cedar Rapids would have another week of minor flooding, starting April 29.
The NWS puts the likelihood of the worst case scenario occurring at between 10 and 25 percent.
The NWS predictions are based on multiple factors in a river basin area, including predicted precipitation, soil moisture levels, river ice, the size of the snowpack and melting trends. The current predictions are based on conditions as of Feb. 18.
The NWS will release an update of its river flooding forecasts on March 7.