Flooding from record rains in a mountainous region of France and Italy has killed two people in Italy and left at least 24 people in the two countries missing. A storm that moved overnight across south-eastern France and then northern Italy caused flooding on both sides of the border, destroying bridges, blocking roads and isolating communities. In Italy’s northern region of Val d’Aosta, a firefighter was killed during a rescue operation. In Vercelli province, a body was found near to where a man had been swept away by flood waters late on Friday. Sixteen people were reported missing in Italy, all but one of them travellers in cars on the Col de Tende high mountain pass between France and Italy, according to civil protection authorities. They included two adults from Germany driving with their 11-year-old and six-year-old grandchildren, and a pair of brothers returning from France. A spokesman for Italy’s firefighters said a search was ongoing for a missing shepherd who was pulled into flood waters on the Col de Tende. The spokesman, Luca Cari, said he suspected that the other people reported missing in Italy had lost phone contact, and they were not currently thought to be in imminent danger. The situation on the high mountain pass was complicated by the fact that French emergency responders could not access their side of a tunnel due to flood damage, Cari said. Italian firefighters were searching the French side for people whose route may have been blocked. In northern Italy’s Piedmont region, overnight rainfall reached levels not recorded since 1958. As much as 630mm (24.8in) of rain fell in a 24-hour period, according to the Italian civil protection agency. Hundreds of rescue operations were under way. Eleven campers were saved in Vercelli province, where flood waters hit 20-year highs. Alpine rescue squads came to the aid of seven people in houses cut off by flooding at Terme di Valdieri. In south-east France, almost a year’s average rainfall fell in less than 12 hours in the mountainous area surrounding the city of Nice. Local firefighters said at least eight people were missing, including two firefighters whose vehicle was carried away by water when the road collapsed during a rescue operation. Nice’s mayor, Christian Estrosi, expressed his “emotion and sympathy” for the families. He said more than 100 homes had been destroyed or severely damaged. Firefighters said several dozen people were evacuated from their homes overnight. The French president, Emmanuel Macron, expressed gratitude to rescuers. “Together we will get through this,” he said.