the montreal flood of 1987 happened on july 14 of that year when a series of strong thunderstorms crossed the island of montreal, canada, between the noon hour and 2:30 p.m. over of rain fell during this very short period of time. the sewer systems were overwhelmed by the deluge and the city was paralyzed by the flooded roads. autoroute 15, a sunken highway also known as the decarie expressway, soon filled with water trapping motorists. some 350,000 houses lost electricity, and tens of thousands had flooded basements. two people died, one in a submerged car and another who was electrocuted.