Himalayan ridge a girl surprisingly ran up (9)
I believe the answer is:
annapurna
'himalayan ridge' is the definition.
(Annapurna is a Himalayan mountain range)
'a girl surprisingly ran up' is the wordplay.
'a girl' becomes 'anna' ().
'surprisingly' indicates anagramming the letters (a surprising ordering of the letters).
'ran'+'up'='ranup'
'ranup' anagrammed gives 'purna'.
'anna'+'purna'='ANNAPURNA'
(Other definitions for annapurna that I've seen before include "Range" , "high ridge" , "Himalayan peak; Hindu goddess of plenty" .)