Many Jamaican communities "will not survive this flooding," said Desmond Mackenzie, Jamaica’s minister of local government and community development.

The slow-moving Melissa strengthened into a major Category 3 hurricane late Saturday as it threatened catastrophic flooding in the northern Caribbean.

The storm is moving at a worryingly slow pace -- just three miles (six kilometers) an hour -- which has meteorologists concerned that it will dump punishing rains on countries in its path for far long...