In Tennessee, more than 22 people are now confirmed dead and many are missing after water overtook entire communities.
Humphreys County Sheriff Chris Davis said many of the missing live in the neighborhoods where the water rose the fastest.
Up to 17 inches (43 centimeters) of rain fell in the county in less than 24 hours on Saturday (August 21, 2021), appearing to shatter the Tennessee record for one-day rainfall by more than 3 inches (8 centimeters), the National Weather Service said.
The hardest-hit areas saw double the rain that area of Middle Tennessee had in the previous worst-case scenario for flooding, meteorologists said. Lines of storms moved over the area for hours, wringing out a record amount of moisture - a scenario scientists have warned may be more common because of global warming.