According to NOAA National Weather Service (NWS)
"Much of the area affected was already wet before excessive rains fell over the first two weeks in June. As a result, the ground could not absorb much of the rain that fell",
... "a large area received more than 8 inches of rain" ...
"Some individual locations received almost a foot".
However, the NWS failed to tell important parts of the whole story. NWS forecasters were caught off guard by the high intensity of the rains in Iowa. Initial NWS flood predictions were woefully inadequate. The public had insufficient time to prepare.
Again and again, NWS says nothing about how climate change is changing hydrology in the Midwest, refuses to allow their hydrologists to research or discuss climate change and continues to operate with an impaired hydrologic model for flood prediction.