In the Flood Policy a flood means:

A general and temporary condition of partial or complete inundation of two or more acres of normally dry land area or of at least two or more properties (one of which is your property) from:

• Overflow of inland or tidal waters.
• Unusual and rapid accumulation or runoff of surface waters from any source.
• Mudflow (Mudflow is defined as a river of liquid and flowing mud on the surfaces of normally dry land areas, as when earth is carried by a current of water. Other earth movements, such as landslide, slope failure, or a saturated soul mass moving by liquidity down a slope, are not mudflows.)

Some causes of floods:

In coastal areas floods can be caused by hurricanes, or if you live by a river or lake, floods can be caused by too much rain falling or snow melting. But in all areas torrential rains, that have no place or inadequate places to go, can cause floods. For instance, if a street drain has been blocked and a torrential rain occurs, an area can experience flooding that had never flooded before.