Flood out
Definition 1 of 2
Pro Tip 1/3Natural Disasters
Used to describe displacement by events like floods or storms. 
The villagers were flooded out after the dam broke.
Pro Tip 2/3Forced Departure
Emphasizes that people had no choice but to leave their homes. 
The entire street was flooded out last night.
Pro Tip 3/3Not Voluntary
Implies leaving wasn't a decision but a necessity due to flooding. 
Residents were flooded out by the rising lake waters.