The overflow of the natural boundaries of a body of water or the unusual and rapid accumulation of surface water runoff. Most insurance policies exclude coverage for flood but coverage can be secured by a separate flood policy. River Flood is the result of rising river and tributary levels and; Flash Flood is caused by a sudden and heavy downpour upstream of the flood zone, the resulting wall of water can move very quickly. Tidal, or Coastal Flooding is caused by surges of wind driven water.