Grand piano in ice storm (4)
I believe the answer is:
epic
'grand' is the definition.
(I've seen this before)
'piano in ice storm' is the wordplay.
'piano' becomes 'p' (musical abbreviation).
'in' means one lot of letters goes inside another.
'storm' is an anagram indicator.
'ice' with letters rearranged gives 'eic'.
'p' going within 'eic' is 'EPIC'.
(Other definitions for epic that I've seen before include "Surpassing the ordinary" , "blockbuster" , "Ben Hur, say" , "Long poem etc" , "Large-scale" .)