Poles were in debt due to what the weather did (6)
I believe the answer is:
'debt due to what the weather did' is the definition.
I can't judge whether this definition defines the answer.
'poles were' is the wordplay.
'poles' becomes 'SN' (North and South poles).
'were' becomes 'owed' (owing is a kind of being).
'in' acts as a link.
Can you help me to learn more?
(Other definitions for snowed that I've seen before include "appeared 26 [WINTRY]", "Endows (anag)".)