How would a gigantic flood effect the east coasts topography/geography?

[AtlanteanCollapse]

hello! I am currently writing a Aftermath! RPG tabletop campaign set in 1989, after the soviets use long dead atlantean artifacts to flood the east coast of America in preparation for an amphibious assault(its a long story). However, I've really only covered the impact of this massive flood on Miami proper. I'm not sure how to quantify the effects of such a large impact- for Miami in particular this is how i describe it two weeks after the massive flood

Zone 1- all land here covered in at least 3 feet of water. all homes damaged, 90% destroyed. all bridges are out and the outlying islands near miami are inaccessible, parts of them are entirely washed away. This extends into downtown miami and biscayne park width wise, and length wise is pretty much up the coast of florida. stops a little outside little Havana, on its southeastern corner.
zone 2- 95% of homes damaged, 75% destroyed. at least 1 foot of water. high rises remain intact, but are rusting. the river that runs through miami has widened and consumed part of the land. runs through little havana to north miami beach, kind of wide at some points
z3- a few inches to no water due to evaporation. most homes here damaged, and some destroyed. most high rises damaged in the first ten floors, and will eventually collapse but at a lesser rate.
z4 and beyond- water flooded here with unknown damage, several new creeks, ponds and lakes have developed. on the border of miami springs and virginia gardens at its furthest point.

If such a flood, in a uniform amount were to hit the entire east coast, what do you guyts reckon would be the most affected areas? are there low-lying zones in some of the northern areas like south carolina, and particularly florida? any mountainous coasts that would weather it well? My idea is that it would've been at its largest, 500 foot waves, and a continual day of wave pounding and severe storms.

included is my image of the map because I feel as though I may have described it poorly.

[Krazma]

Have you considered using the existing FEMA flood maps as a guide? https://hazards-fema.maps.arcgis.com...9338b5529aa9cd