The rapid snowmelt in Spring 2019 has caused instances of stored grain being covered with floodwater. By current Food and Drug Adminstration (FDA) policy, grain inundated by uncontrolled river or stream water is considered adulterated and must be destroyed. The situation in 2019 is one of river water flooding rather than of rain-driven pooled water in low ground, for which there are salvage options. As shown by the example of the inundated Omaha sewage treatment plant, river-based floodwaters can bring in many hazards and rapid spoilage.
Iowa State University
Hurburgh, Charles R., "Flooding and Stored Grain" (2019). Integrated Crop Management News. 2524.