A minor disturbance (6)
I believe the answer is:
ripple
'a minor disturbance' is the definition.
The definition and answer can be both related to natural events as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for ripple that I've seen before include "Edgar Allan ---, US author" , "Light ruffle on the surface" , "Small wave or surface disturbance" , "Slight disturbance on water's surface" , "Slight surface wave" .)