The area was not prepared for excessive rain and associated flooding. They need to stage practice emergency evacuation procedures for areas such as this.
They need to get out of town when they say it’s heading your way. So many of these towns were in valleys...
Nobody plans for 20 to 30 inches of rain in a day so. My mostly flat midwestern town isn’t likely to handle 10 inches of rain during a day or so rain event.
Pretty much all of us do. If it’s not hurricanes or floods, it’s tornadoes or earthquakes or mudslides or volcanoes.