1 For more information on flood zones, see FEMA's FloodSmart web page. 2  Zone AE are areas that have a 1% probability of flooding every year (also known as the 100-year floodplain), and where predicted flood water elevations above mean sea level have been established. Shaded Zone X are areas that have a 0.2% probability of flooding every year (also known as the 500-year floodplain). 2  Properties in Shaded Zone X are considered to be at moderate risk of flooding under the National Flood Insurance Program.
The Great Plains is the broad expanse of flat land, much of it covered in prairie, steppe and grassland, that lies west of the Mississippi River tallgrass prairie states and east of the Rocky Mountains in the United States and Canada.he Great Plains are the westernmost portion of the vast North American Interior Plains, which extend east to the Appalachian Plateau. The United States Geological Survey divides the Great Plains in the United States into ten physiographic subdivisions:
The continent can be broken into four major landform regions: the Coastal Plains, the Eastern Highlands, the Central Lowlands and the Western Plateau. These landform regions have been created by movements in the Earth's crust, river erosion and changes in climate and sea level.