Last week, researchers at the University of California, Davis, overlaid FEMA’s flood-zone maps on top of satellite imagery of the devastating flooding around Houston after Harvey poured more than 40 inches of rain across the region.
The preliminary assessment found that two-thirds of the inundation occurred outside the federal agency’s 100-year floodplains, where there should be only a 1 percent chance of flooding in any given year. More than half of the deluge happened “outside of any mapped flood zone,” even including 500-year events, in areas that should face only “minimal flood hazard” . You can read more here.
Similar instances were observed when hurricane Katrina hit the US few years ago. The predictions went wrong because of the computer models relying on data which is of no relevance today.