ANTIBES, France—In a matter of minutes, torrential rains transformed the postcard-perfect French Riviera into a terrifying flood zone, leaving at least 16 dead, trapping hundreds of ailing pilgrims, and halting car and train traffic Sunday along the mud-drenched Mediterranean coast.
Victims were found dead in a retirement home, campsites, and cars submerged in a tunnel. Residents, stunned by the ferocity of the brief downpour Saturday night, described it as the worst flooding they'd ever seen—so dramatic that President François Hollande paid an emergency visit Sunday to promise government aid for victims.
The Cannes region saw the equivalent of two months of rainfall in less than two hours.
