Bank blown up in winter? (9)
I believe the answer is:
snowdrift
'bank' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for snowdrift that I've seen before include "evidence of wintry weather" , "Wind-driven winter hazard" , "Feature of winter weather" , "Winter problem" , "Weather problems" .)