A howl from lost hikers (6)
I believe the answer is:
shriek
'a howl' is the definition.
(I know that shriek is a type of howl)
'lost hikers' is the wordplay.
'lost' indicates an anagram.
'hikers' anagrammed gives 'SHRIEK'.
'from' acts as a link.
(Other definitions for shriek that I've seen before include "Shrill cry of a shrike" , "Hikers (anag.)" , "Utter high-pitched cry" , "Yell, screech" , "Sharp piercing cry" .)