Update: 7.25 a.m. EDT - According to a report on Sky News,  13 people have died and five others were injured due to the flash flooding in France. 

Prime Minister Edouard Philippe said he would visit Aude Monday afternoon "as soon as conditions allow it". He also said "350 firefighters are in place. 350 more firefighters are on their way. 7 helicopters have been mobilized. I am keeping myself informed of the situation hour by hour."

Original story:

At least six people died due to flash flooding in Aude, France, the local government authorities said Monday.

According to reports, a nun was washed away by the flood waters. Two others who were reported missing were found dead, and another was killed when a house collapsed on the person, reports said.

Heavy rains in the area for a few hours overnight caused flash flooding, with one river rising by more than 20 feet, Sky News reported. Many people are stranded on rooftops and rescue teams are working to save them.

“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," Alain Thirion, the prefect of Aude, said according to a report on Sky News. He added helicopters were waiting for clearer weather to launch rescue operations.

Reports said water levels were expected to rise again Monday with rain lasting until late in the morning. Residents were asked to stay at home, while all schools and colleges in the area remained closed Monday.

Aude was placed on red alert, the highest flood warning, due to the rain and flooding by France's national weather agency Meteo France on Monday morning. This means people in the area should practice "absolute vigilance" as there was a higher risk due to "dangerous weather of an exceptional intensity."

Thirion said the municipalities of Villemoustaussou, Villegailhenc, Conques, Villardonnel, Floure and Trèbes were the most affected. The water levels in Trèbes climbed eight meters (more than 26 feet) in five hours Monday, while it rose as high as the first floor windows of some houses located in the villages of Conques-sue-Orbiel and Veillardonnel.

Aude administration tweeted Monday that people in Pezens and Cuxac-d'Aude were evacuated. Beds and blankets were made available for evacuees at Palais du Travail (Palace of Labor) in Narbonne. Trains services were also suspended.  

The flooding reached beyond seven meters (more than 22 feet) in some areas, the highest since 1891, in Aude on Monday. More than six helicopters and 250 firefighters were deployed to the region to rescue stranded residents.

Meteorologists said the exceptionally warm sea water along the Mediterranean coast of southern France might have caused the heavy rainfall, adding that torrential rains were not uncommon in France in this time of the year, reported Daily Star. France witnessed the hottest season since 1900 this year, according to the state meteorological service. 

A report in the French daily The Local said six other departments in south-eastern France — Aveyron, Herault, Tarn, Tarn-et-Garonne, Haute-Garonne and Pyrenees-Orientales — were placed on orange alert, the second highest warning, due to heavy rains and floods.

This is a developing story.