The most common and most likely answer to this crossword clue is the 7 letter word ENGULFS
I've seen this crossword clue in The Daily Telegraph
E
N
G
U
L
F
S
Buddy explains!

The straight part
We know that "floods" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case floods = engulfs.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ENGULFS mean?
ENGULFS verb- To overwhelm.
- To surround; to cover.
- To cast into a gulf.