A lot of snow, one foot, at end of drive (5)
I believe the answer is:
drift
'a lot of snow' is the definition.
'one foot at end of drive' is the wordplay.
'one' becomes 'i' (Roman numeral**).
'foot' becomes 'ft' ('ft' can be a synonym of 'foot').
'at end of' means one lot of letters go next to another.
'drive' becomes 'dr' (I've seen this in other clues).
'i'+'ft'='ift'
'ift' put after 'dr' is 'DRIFT'.
(Other definitions for drift that I've seen before include "Gist - snow" , "Large heap (of snow)" , "Trend; meaning" , "Be powerless to control movement" , "Go with the flow" .)