If a fire ant colony is flooded during a rainstorm or other high-water situation, the ants cling together and form a living raft that floats on the flood waters. Once the raft hits dry ground or a tree, rock, or other dry object, the ants can leave the water.
Footage Shows Massive Colonies of Fire Ants Floating in Hurricane Florence Floodwaters (Sep 18, 2018)
Floodwaters will not drown fire ants. In the wake of Hurricane Florence, victims in the storm's path are being warned to avoid wading through dangerous floodwaters (in addition to other reasons and threats).