At least 51 people have died in Spain’s eastern region of Valencia after flash floods swept away cars, turned village streets into rivers and disrupted rail lines and major roads in the worst natural disaster to hit the nation in recent memory.

Emergency services in Valencia confirmed the death toll on Wednesday.

Rainstorms on Tuesday caused flooding in a wide swathe of southern and eastern Spain.

Floods of mud-coloured water tumbled vehicles down streets at frightening speeds. Pieces of wood swirled with household articles.

Police and rescue services used helicopters to lift people from their homes and cars.

People walk through flooded streets in ValenciaPeople walk through flooded streets in Valencia (Image: (Alberto Saiz/AP))

Authorities reported several missing people late on Tuesday, but the following morning brought the shocking announcement of dozens found dead.

More than 1,000 soldiers from Spain’s emergency response units were deployed to the devastated areas.

“Yesterday was the worst day of my life,” Ricardo Gabaldon, the mayor of Utiel, a town in Valencia, told national broadcaster RTVE.

He said several people were still missing in his town.

“We were trapped like rats. Cars and trash containers were flowing down the streets. The water was rising to three metres,” he said.

Spain has experienced similar autumn storms in recent years, but nothing compared to the devastation over the last two days.

The death toll could easily rise with other regions yet to report victims and search efforts continuing in areas with difficult access.

In the village of Letur in the neighbouring Castilla La Mancha region, mayor Sergio Marin Sanchez said six people were missing.

Valencian regional president Carlos Mazon urged people to stay at home so as not to complicate rescue efforts, with travel by road already difficult due to fallen trees and wrecked vehicles.

“The neighbourhood is destroyed, all the cars are on top of each other, it’s literally smashed up,” Christian Viena, a bar owner in the Valencian village of Barrio de la Torre, said by phone.

“Everything is a total wreck, everything is ready to be thrown away. The mud is almost 30 centimetres deep.”

Spain’s central government set up a crisis committee to help co-ordinate rescue efforts.