Flora came ashore in Haiti and then stalled over eastern Cuba, looping for about four days in October 1963 instead of moving on. The rain kept falling on the same mountains — totals above a hundred inches in places — and the rivers in Oriente took the valleys below them. At least seven thousand people died across the Caribbean, most of them in Haiti and Cuba, and the counting went on for weeks after the water went down.
The mountain gauges in Oriente recorded over 2,500 millimetres in those four days — roughly a hundred inches, most of it onto slopes already saturated. Rain like that has nowhere to go but down into the valleys where people live.
The dying doesn't stop when the river does, Kit. After floods like that the water supply is the problem — wells and standpipes contaminated, so gastroenteritis and typhoid follow, and in 1963 much of the rebuilding in Oriente was about clean water and roofs before anything else. The counting went on partly for that reason.