This gallery is part of a special National Geographic News series on global water issues.
Robert Sanders rows past his Holly Grove, Arkansas, home atop Mississippi River floodwaters Tuesday with his dog—aptly named Lucky. Many pets along the Mississippi River and its tributaries are at risk as the river swells, according to a Wednesday statement by the Humane Society of the United States (HSUS).
"The HSUS is prepared to temporarily shelter any animal displaced by the floods; please remember, if it is not safe for you, it isn't safe for your pets," said Lydia Sattler, Mississippi state director for the HSUS.
Earlier this week, the Mississippi River peaked in Memphis, Tennessee, just inches below the all-time record, according to the National Weather Service. Now the surge is continuing south toward the Gulf of Mexico, where New Orleans is bracing for its own crest around May 23.
—With reporting by Brian Handwerk