(Reuters) - The rising Mississippi river lapped over downtown Memphis streets on Thursday as a massive wall of water threatened to unleash near record flooding all the way to the Gulf of Mexico.

Water lapped over Riverside Drive and onto Beale Street in Memphis, and threatened some homes on Mud Island, a community of about 5,000 residents with a river theme park. The island connects to downtown Memphis by a bridge and causeway.

Emergency officials in Millington near Memphis were "going door-to-door, asking people to leave," according to the Tennessee Emergency Management Agency.

Large amounts of rain and melt from the winter snow has caused a chain reaction of flooding from Canada and the Dakotas through Illinois, Indiana, Missouri, Kentucky, Arkansas and Tennessee. It is expected to soon hit Mississippi and Louisiana at the mouth of the Mississippi River.

The flood threat harkens back to memories from the aftermath of Hurricane Katrina in which Mississippi beachfront towns were engulfed and most of New Orleans went under water after its levee system failed.

"The flood is rolling down, it is breaking records as it moves down and it is one of those wait-and-see type of things as to how massive it is going to be when it's all said and done," said Charles Camillo, historian for the Mississippi River Commission and the Mississippi River and Tributaries Project.

Read more here.