Pile of snow, in essence (5)

I believe the answer is:

drift

I'm a little stuck... Click here to teach me more about this clue!

This clue could be a double definition.

'pile of snow' is the first definition.
'drift' can be an answer for 'pile' (thesaurus). I am not sure about the 'of snow' bit.

'essence' is the second definition.
(thesaurus)

'in' is the link.

Can you help me to learn more?

(Other definitions for drift that I've seen before include "Be slowly carried by a current" , "non-standard deviation?" , "Move casually or aimlessly" , "Slide" , "Stray" .)

I've seen this clue in The Times and The Sunday Times.

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