PARIS, Oct. 15 (Xinhua) -- Torrential and sudden rainfall had triggered an unprecedented rise in water levels in the southern French department of l'Aude where at least six people were reported dead overnight, French regional authorities said on Monday.

According to Alain Thirion, prefect of Aude, six people lost their lives after being swept away by raging water. Another person was wounded following the collapse of his home.

"We continue to have information about the situation and the death toll risks to rise," he was quoted as saying by local media.

"We have people stranded on rooftops. We're going to have to use aircraft to evacuate them because we cannot reach them by boat given the force of the water. It's too dangerous," he said.

Seven months worth of rain fell in just a few hours overnight in southwestern France. The villages of Conques-sur-Orbiel, Trebes and Villardonnel were the worst-hit zones where rail traffic was suspended, roads and schools remained closed on Monday.

Authorities had ordered the evacuation of about 1,800 inhabitants in Pezens and recommended people in the affected areas to stay at home.

French weather agency Meteo France has put l'Aude under red alert and six other areas under orange alert on risks of floods and torrential rainfall. It decided to maintain the alert system in these areas until Tuesday morning. Enditem