All towns west of Atchafalaya River as far as 29 miles* have the risk of flooding.

Morgan City & Simmesport: Flood Risk - 99%
Lafayette: Flood Risk - 92%


Breaux Bridge, Carencro, Opelousas, Port Barre, Broussard, St. Martinville,
New Iberia, Jeanerette, Franklin, Patterson, Morrow, Cottonport: Flood Risk - 83%


*Yes, 29 miles! The amount of water displacement is enormous:
Almost 1.91 greater than Australian floods and 0.92 greater than the Japan Tsunami!



Also at risk of flooding some towns near the mouth of Red River by backwards flow:

Alexandria: Risk 92% (Backwards flow)
Effie: Risk 83% (Backwards flow)

Marksville & Lecompte: Risk 74% (Backwards flow)



Of course, no need to mention that all the towns near Mississippi River are also at high risk
of severe flooding and sudden underground water collapse (sink-holes) specially:

New Madrid at Missouri
Memphis at Tennessee
Baton Rouge & New Orleans at Louisiana

Links:
[link to upload.wikimedia.org]
[link to en.wikipedia.org]
[link to en.wikipedia.org]
[link to upload.wikimedia.org]
[link to www.ssd.noaa.gov]
[link to www.wunderground.com]