I lived in North Dakota during the Great Red River Flood of 1997. You haven’t seen anything until you’ve seen an entire city of 50,000 people evacuated. Families with nothing left but the clothes on their backs.
Even if you’re outside the lines on FEMA’s Flood Insurance Rate Maps (FIRMs), use your own best judgement. The engineers who delineate the flooplains work hard to get it right, but they’re only human and have imperfect information at hand.
Go out and talk to the neighbor that’s lived on your block the longest—if they’ve seen the water there before, it’s probably coming back again. When you’re not looking. We do our best to mitigate the effects of disasters, but it’s up to you as an individual to be prepared.