Fatalities is the hard one. There will always be a percentage of the population that won't take basic precautions or waits until the last minute to do so.

Property on the other hand is relatively easy. Whenever a disaster destroys a significant portion of the area (i.e. Hurricanes Andrew, Katrina, & Harvey) the local building code needs to be revised.

Another option would be to change Federal flood insurance to be good for one unmodified rebuild. If they don't take steps to prevent damage from the next one, they don't get rebuilt again.