At least nine people have died over the weekend, as torrential downpours drenched parts of the south-eastern US, submerging roads and houses.
Hundreds of people stranded in flood waters, many stuck in their cars, had been rescued.
In Georgia, the ninth death was recorded after a man lying in his bed was struck by an uprooted tree that crashed into his home.
Kentucky, Georgia, Alabama, Mississippi, Tennessee, Virginia, West Virginia, and North Carolina were under some type of storm-related alert this weekend. Almost all of those states suffered catastrophic damage in September from Hurricane Helene.
Between the eight states, more than half a million households were without power on Sunday night, according to poweroutage.us.
A bulk of the death and destruction appears to have occurred in Kentucky, where a mother and her seven-year-old child and a 73-year-old man were among the dead.
Some parts of Kentucky received up to 6in (15cm) of rain, National Weather Service (NWS) figures show, resulting in widespread flooding issues.
President Donald Trump approved the declaration on Sunday, authorizing the Federal Emergency Management Agency (FEMA), which he has suggested abolishing, to co-ordinate disaster relief efforts.
Officials have cautioned that the worst of the flooding is not over yet.
