Power failure crossing river creates shock (7)
I believe the answer is:
outrage
'shock' is the definition.
(I've seen this before)
'power failure crossing river' is the wordplay.
'power failure' becomes 'outage'.
'crossing' means one lot of letters goes inside another.
'river' becomes 'r'.
'outage' going around 'r' is 'OUTRAGE'.
'creates' is the link.
(Other definitions for outrage that I've seen before include "Very angry reaction" , "Act that shocks public opinion, generates anger" , "Profound indignation" , "Violate" , "Great anger" .)