A general and temporary condition of partial or complete inundation of normally dry land areas from (1) overflow of inland or tidal waters, (2) the unusual accumulation and runoff of surface waters from any source, or (3) abnormal, flood-related erosion and undermining of shorelines. Flood also means inundation from mud flows caused by accumulations of water on or under the ground, as long as the mud flow and not a landslide is the proximate cause of loss.