WASHINGTON (AFP) - President Joe Biden has declared a major disaster in the southern US state of Tennessee and approved federal funding after devastating floods over the weekend left at least 21 dead, the White House said in a statement said on Tuesday (Aug 24).

Tennessee was hit last Saturday by what meteorologists called historic storms and flooding, dumping as much as 43cm of rain.

Rural roads, state highways, bridges and hundreds of homes were washed out and widespread power outages affected thousands of people.

The move makes federal funding available to people affected in Humphreys county, where the downpour last Saturday broke a 24-hour rainfall record for Tennessee, the National Weather Service said.

Help for residents includes "grants for temporary housing and home repairs", as well as "low-cost loans to cover uninsured property losses", the White House said.

Floods are natural phenomena, but climate change is altering Earth's rainfall patterns, making some regions wetter and others drier.

Scientists say climate change is intensifying the risk of heavy rain around the world, because a warmer atmosphere holds more water.

According to an international study published on Tuesday, climate change made the deadly floods that devastated parts of Germany and Belgium last month up to nine times more likely.