What has caused the flooding disaster in Tennessee?

Heavy rain has caused unprecedented levels of flooding in Tennessee, killing 22 people with many more still missing.

Humphreys County, west of Nashville, saw up to 17 inches of rainfall on Saturday – beating the state’s previous record for one-day rainfall by more than three inches, according to the National Weather Service.

The rain and flooding have devastated scores of homes in the area. Communications infrastructure, including cell towers and phone lines, were knocked out by the water, leaving families uncertain whether loved ones had survived. Twin seven-month-old babies were among the victims in Waverly, which faced its worst flooding since the late 1970s. Rescue crews were going door to door in their recovery efforts.

In 2010, Nashville experienced a devastating flood that broke every rainfall record to date when 13 inches of rain fell over 36 hours, killing more than two dozen people. The flood left $2.3bn (more than £1.6bn) in property damage in its wake, leading local government officials to invest in flood prevention. The state government knocked down 300 homes that were prone to flooding in Nashville, purchased homes lying in flood-zone areas, and invested millions of dollars in drainage systems.

While those efforts may help Nashville deal with floods in the future, the mitigation efforts were not adopted statewide.

In 2020, US Rep Jim Cooper sponsored a bill that allowed two dams in Nashville to be used to control future floods, but the state’s plan doesn’t cover flooding that occurs in other areas of the state, leaving many people unprotected.

President Joe Biden pledged the resources of the federal government to help the storm-stricken area.

“We’ve reached out to the community and we stand ready to offer them support,” the president said after offering his condolences from the White House.

In a landmark United Nations report, researchers found that extreme weather – like heavy rains, which can trigger flash floods – will become more frequent because of the climate crisis. However, Krissy Hurley, a National Weather Service meteorologist in Nashville, said it was impossible to know the extent to which the climate crisis had contributed to the weekend rain. But she did concede the historic nature of the flooding.

“Forecasting almost a record is something we don’t do very often,” Ms Hurley said. “Double the amount we’ve ever seen was almost unfathomable.”

Tennessee has experienced other floods in the past few years. In September 2020, the south of Tennessee saw major flash-flooding, and the middle of Tennessee had the same weather conditions in March 2021. Six people died as a result of the floods in March.

In general, yearly rainfall in Tenessee has increased by five per cent since the first half of the century, according to the Environmental Protection Agency. In the southeast region of the state, rainfall has increased by 27 per cent since 1958.

With additional reporting by the Associated Press