Systems and methods for modeling floods

A flood modeling system defines virtual cells of a geographic region. Some of the cells, referred to as "channel cells," represent areas within a channel for a moving body of water, such as a stream or river. Other cells, referred to as "land cells," represent areas external to the channels within the geographic region. The flow of water through the geographic region is modeled as a virtual flow of water through the channel cells and the land cells. For each time step, the system calculates the amount of water that virtually flows out of one cell into adjacent cells. The water estimated to virtually flow above ground represents flood water, and the estimates of such water can be used to generate an inundation map or initiate flood warnings.