With climbers furious, short of peak, expedition leader dug in (5)
I believe the answer is:
ivied
'with climbers' is the definition.
(covered in ivy)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for ivied that I've seen before include "Covered with climbing plant" , "Covered in Hedera helix" , "Overgrown with creeper" , "Covered with creeper" , "with covering of creeper" .)