Eight people remained unaccounted for in France after storms, torrential rain and flash floods battered the area, washing away roads and houses, cutting off entire villages and triggering landslips.

In Breil-sur-Roya, a French village close to the Italian border, houses were buried in mud and turned-over cars stuck in the riverbed.

Emergency personnel walk amongst debris on a street in Breil-sur-Roya, south-eastern France, on October 4, 2020, after extensive flooding caused widespread damage in the Alpes-Maritimes departement. AFP

Storm Alex barrelled into France's west coast on Thursday bringing powerful winds and rain across the country before moving into northern Italy.

“What we are going through is extraordinary,” said Bernard Gonzalez, prefect of the Alpes-Maritimes region, after as much as 60 centimetres (two feet) of rain fell in 24 hours in the worst-affected areas.

France has declared the region a natural disaster zone.

Saint-Martin-Vesubie, a French village home to 1,400 north of Nice, was completely cut off by the storm.

This aerial view taken on October 3, 2020 shows the damage in Saint-Martin-Vesubie, southeastern France. Valery HACHE / AFP

A bedraggled group of tourists and residents gathered in the village square to be airlifted to safety, an AFPTV journalist said after reaching the site on foot.

“My three-storey house, it's in the river,” said villager Sandra Dzidt, 62, who had to flee the floods dressed only in her nightgown. “All I have left is a tiny piece of wall and a door.”

Across the region, emergency crews were handing out food and airlifting thousands of bottles of water into remote villages cut off by the storms.

I lost everything but we are alive,” said Jennyfer, 29, from Roquebilliere in France's southern Alps.

“There must be one room left in my house,” she said after she returned following evacuation on Friday to survey the damage wrought by the Vesubie river.

A woman looks out over a pile of mud on a street in Breil-sur-Roya, south-eastern France, on October 4, 2020.NICOLAS TUCAT / AFP

An emergency spokesman in France said that around 40 people stranded on roads by the landslides had sheltered in an old train station and then been airlifted to safety.

The army and hundreds of rescuers were deployed to search for the missing, including using helicopters to transport aid and evacuate people where possible.

AFP journalists who reached one of the worst-hit areas in the Vesubie valley saw roads that had been washed away by the waters leaving buildings teetering above the voids.

This aerial view taken on October 3, 2020 shows the damage in Saint-Martin-Vesubie, southeastern France, after heavy rains and floodings hit the Alpes-Maritimes department.  Valery HACHE / AFP

'Helicopter procession'

French Prime Minister Jean Castex inspected the damage by helicopter on Saturday, saying he feared the number of people missing could rise after dozens of cars and several houses were swept away in apocalyptic scenes.

Alpes-Maritimes prefect Bernard Gonzalez called on the families of the missing not to give up hope.

“Just because their loved ones haven't been able to get in touch doesn't mean that they have been taken by the storm,” he said.

Many landline and some mobile phone services were disrupted, with some villages using satellite phones to communicate with rescue services.

Despite forecasts of more rain, rescue efforts were to continue throughout Sunday, Gonzalez said.

“The helicopter procession will continue all day long,” he said.

This aerial view taken on October 3, 2020 shows flood waters surging through Saint-Martin-Vesubie, southeastern France, after heavy rains and floodings hit the Alpes-Maritimes department. Valery HACHE / AFP

Authorities in the Alpes-Maritimes region had been placed on alert Friday and around 12,000 people in three valleys to the north of Nice were without power early Saturday afternoon.

“We are thunderstruck,” said Serge Franco, a resident of Roquebilliere, some 50 kilometres (30 miles) north of Nice, as rescue helicopters hovered overhead.

“We saw the (river) Vesubie burst its banks — everything was swept away, including part of the old iron bridge,” he told AFP.

“My house is habitable but half of my land has been swept away,” said another resident, Guillaume Andre. Evacuated overnight, he had returned to see the devastation after daybreak.

In Roquebilliere, the floodwaters swept away two elderly people with their house.

“The firefighters did not have enough rope, and even with our rope we could not reach the house, so it was too late to get to them and the house was suddenly swept away,” resident Patrick Theus told AFP.

The Var river was also subject to a red warning for floods as water levels rose to record levels, according to some reports.

Beaches in Nice and other coastal cities were closed, and authorities asked people to stay at home and refrain from using their cars unless in case of emergency.

Roads were left submerged by the rising waters as this image near the town of Carros shows.

The scene in Nice on Friday. AFP