Just off of the top of my head on the "worst natural dissasters" convo...
In no particular order, except that they are all ahead of the afore mentioned Cederwhoosit flood:
Mt. Saint Hellen's
Earthquake in San Fran the first time around (entire town leveled back before talkies were the rage)
Earthquake in San Fran when it interrupted the World Series and those dudes were pancaked under freeways collapsing.
Hurricane Andrew in Florida...the one that basically removed Homestead Florida from the map.
Hurricane Katrina, the one that made people rape each other in the superdome.
Hurricane in the Carolinas that scalped the coast in the early 90's/late 80's
Flood of the summer of 1993 down the entire length of the Missisippi
That's just off of the top of my head...