Torrential rain and flash flooding has killed at least 16 people in Kentucky.
Governor of the US state, Andy Beshear, said the death toll, which includes six children, is likely to rise.
The floods have been declared "a major disaster" by US President Joe Biden, who has ordered federal aid as more than 23,000 people in the state have been left without power.
Mr Beshear, who was given an aerial tour of the damage wreaked by the flooding, described it as "by far the worst" he has witnessed.
He said hundreds of homes have been wiped out as a result of the flooding, which was caused by heavy rains earlier in the week.
More than 20cm of rain was recorded over 24 hours in some parts of the state.
The governor is urging people to have a safety plan prepared as further rainfall is forecast for early next week.
Local rescue efforts are being aided by agents from the US Federal Emergency Management Agency.
The total number of people affected or missing is unclear at present, said Mr Beshear, because of difficulty gaining access to some areas due to damaged parts of 28 roadways in the state.
He confirmed the tragic deaths of four young siblings - the eldest being eight years old and youngest aged just one - in the floods.
Speaking to the Lexington Herald-Leader, the children's cousin, Brittany Trejo, described the efforts of their parents to protect them from the flooding as they sheltered under a tree.
She said: "They managed to get to a tree and ... held the children a few hours before a big tide came and washed them all away at the same time."
She added that it took eight hours for the mother and father, who survived and were left stranded at the tree, to be rescued.
Kentucky is another area that is experiencing extreme weather events as global heating and climate breakdown impacts the world.
