Heavy floods have forced the evacuation of 1,600 people – most of them campers – in southern France, officials say.
They say a 70-year-old German man who was helping to supervise children at one of the summer camps is missing.
The worst-hit areas are Gard, Ardèche and Drôme. More than 400 firefighters and police – as well as four helicopters – have been deployed.
The flooding comes after southern France – and much of Europe – experienced unusually hot weather.
In a statement (in French), the French interior ministry said six departments were placed on a flood alert, while about 17,000 homes were without power in the south-west and north-east.
In one summer camp in Saint-Julien-de-Peyrolas, in the Gard region, 119 children were evacuated. One camper told French television network BFM they could hear the children’s cries “in the branches”, but was unable to reach them.
The missing German was supervising the children at the camp.
Trapped by a fast-flowing torrent, he sought shelter inside his caravan – but the vehicle was swept away, AFP news agency reports. It was later found “empty and in pieces”, according to police.
Divers were called in, as the search operation continued.
Regional police spokesman Jérôme Tallaron said 10 people had been taken to hospital with hypothermia and minor injuries, according to the news agency.
Harry Ollerton, from Shropshire, in the UK, was camping in the Ardèche when he was woken at 05:00 on Thursday to “the loudest thunder and brightest flashes of lighting”.
“It didn’t let up – the lightning was constant and terrifyingly close to our tent and campsite,” he told reporters.
“It passed straight over us, knocking out the power to our pitch and our phone signal suddenly went dead.”
After realising a nearby drainage ditch was overflowing, Mr Ollerton decided it was no longer safe to stay – but even the drive to the nearest town was difficult.
“Village streets had turned into rivers and the rain was so hard that we couldn’t barely see out of the window,” he said.
“Some of the roads were so flooded that they were barely passable. We were lucky to make it out of the area, soaked through but unharmed, by the sound of things.” Ollerton added.
Rachel Buchanan, from Oxford in the UK, was also camping in the Ardèche when flooding hit.
“We knew a storm was imminent and couldn’t believe the ferocity of last night’s storm,” she told reporters.