Fools around with large snowdrifts (6)
I believe the answer is:
clowns
'fools' is the definition.
(clown is a kind of fool)
'around with large snowdrifts' is the wordplay.
'around' becomes 'c' (abbreviation for 'circa').
'with' means one lot of letters go next to another.
'large' becomes 'l'.
'snowdrifts' becomes 'owns' (I can't justify this - if you can you should give a lot more credence to this answer).
'c'+'l'+'owns'='CLOWNS'
(Other definitions for clowns that I've seen before include "idiotic people" , "Funny circus folk" , "Circus comedians" , "Funny men in the circus" , "They amuse with ridiculous behaviour" .)