The National Flood Insurance Program (NFIP) defines a floos as
- A general and temporary condition of partial or complete inundation of 2 or more acres of normally dry land area or of 2 or more properties (at least 1 of which is the policyholder's property) from:
--Overflow of inland or tidal waters; or
--Unusual and rapid accumulation or runoff of surface waters from any source; or
- Collapse or subsidence of land along the shore of a lake or similar body of water as a result of erosion or undermining caused by waves or currents of water exceeding anticipated cyclical levels that result in a flood as defined above.