Hours before a river of mud descended on towns around Valencia, trapping and killing hundreds of people, water started gushing through the small Spanish municipality of Utiel.

A quiet winemaking town on the upper reaches of the Magro River, inland from Valencia, Utiel sits about an hour’s drive from the sprawling, densely populated eastern coast of Spain that was inundated last month in some of Europe’s worst flooding in decades.

Heavy rains began in Utiel on the morning of Oct. 29. By about 1 p.m., the town’s narrow cobblestone streets were already filled with several inches of water. By 2 p.m., a muddy tide nearly reached the windows of the town’s low homes as the Magro spilled over its banks. Trash cans and cars drifted about like toy boats. By 3 p.m., the mayor said that he had alerted the firefighters and the military emergency unit.

“Everyone knew that we were drowning,” said the mayor, Ricardo Gabaldón.

Yet the regional authorities failed to alert towns and villages a few dozen miles lower down the Magro that the river was raging and coming their way, mayors said. Hours later, it hit those places, too.

“I don’t know why they didn’t warn us,” said José Javier Sanchis Bretones, the mayor of Algemesí, which was flooded in the evening, killing at least three people there.