Has to be drifting snow (4)
I believe the answer is:
owns
'has' is the definition.
('own' can be a synonym of 'have')
'drifting snow' is the wordplay.
'drifting' is an anagram indicator.
'snow' is an anagram of 'OWNS'.
'to be' is the link.
(Other definitions for owns that I've seen before include "Has possession of by right" , "Possesses" , "uses" , "Admits possession" , "Belongs to" .)