So, how much is a 3 meter rise? There seems to be heavy demand on the interactive maps scattered around the Internet, but a 2004 National Geographic article gives a good feel.
The maps show that a 1-meter (3-foot) rise would swamp cities all along the U.S. eastern seaboard. A 6-meter (20-foot) sea level rise would submerge a large part of Florida.
. . .
A one-meter sea level rise would wreak particular havoc on the Gulf Coast and eastern seaboard of the United States.
"No one will be free from this," said Overpeck, whose maps show that every U.S. East Coast city from Boston to Miami would be swamped. A one-meter sea rise in New Orleans, Overpeck said, would mean "no more Mardi Gras."
If you can get through to it, there's an interactive system here. There is also a collection of static maps here.