Some people in the low-lying working-class neighbourhoods of Poza Rica heard the wall of water before they saw it. The loudest sound was from the cars crashing together as they were swept along by the water that had escaped from the banks of the Cazones River and flooded the streets with more than 12 feet (4 meters) of water at dawn Friday.

On Saturday, much of that water had flowed away. What was left was pure destruction, and the sometimes head-scratching combinations made when nature collides with the man-made: like cars hung in treetops and even a dead horse wedged inside the cabin of a pickup truck.