Deficiency that may presage long winter in Canada? (9)
I believe the answer is:
shortfall
'deficiency' is the definition.
(I know that shortfall is a type of deficiency)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for shortfall that I've seen before include "Loss" , "what we're lacking" , "lack" , "Not quite what's expected" , "Deficit of something required" .)