A British holidaymaker has described a “raging river” near her campsite in southern France after flash flooding forced the evacuation of hundreds of people.

Heavy rain in the Gard, Ardeche and Drome areas, popular with British campers every summer, has destroyed tents and inundated streets.

Some 1,600 people, many of them children, were evacuated, and a 70-year-old German man helping to supervise youngsters at a summer camp in Saint-Julien-de-Peyrolas in the Gard region was feared to have been swept away by floodwater, along with his van.

Nearly 120 children were evacuated from the site as emergency teams helped around 750 people to safety across the Gard area.

Kathryn Alford, 44, from Welwyn Garden City in Hertfordshire, was at Huttopia Camping Le Moulin in Saint Martin d’Ardeche with her husband and two children.

She said severe storms started at around 7am on Thursday with very heavy rain and constant thunder and lightning.

“I looked out at one point and realised that the water level seemed higher than just massive puddles. Our neighbour’s bottom step had disappeared and things were floating past,” she said, adding that they had lost electricity.

Between storms, Ms Alford took pictures of people in canoes in the flood outside the mobile home she was staying in.

“I was quite frightened at first as I hate storms. Some people were concerned, but the campsite were good at reassuring us.

“I felt really sorry for the people whose tents were flooded,” she said.

Ms Alford said the fire brigade came to the site to pump out water which came down suddenly from the hills.

“When things had calmed down around four-ish we went down to the village and were met by the sight of water pouring down streets from hills into a completely changed raging river,” she said, referring to the Ardeche river, which had been tranquil the previous day.

Rachel Buchanan, from Oxford, endured a “frightening” drive through floodwater that had hit another site in the Ardeche region.

“The level and speed of the river today was extraordinary – we woke up in about a foot of water,” she told the BBC.

“Driving in our camper van was very frightening as the road by the river was completely under water and waterfalls had appeared from nowhere, crashing down the gorge.”

The French weather service has issued orange and yellow alerts for parts of south-east France which will remain in place until 4pm on Friday.

UK Met Office meteorologist Marco Petagna said nearly 3in (7.6cm) of rain fell over the area in 24 hours.

“It’s located in the area of hot weather that has been affecting much of Europe just recently, although there is a cold front moving south,” he said.

“Where you have got cold air trying to come in, at the boundary the hot air rises quite quickly and creates these rain clouds.

“There are still storms around, although they are starting to ease a little bit.”

He said parts parts of the Mediterranean could still see wet weather, with the Balearic islands and Sardinia at risk of heavy rain.