Chewbacca and Han remained with the Rebel Alliance after the Battle of Yavin, and helped establish its new base on the ice planet Hoth. But Han had to pay off Jabba the Hutt, meaning he and Chewie would be forced to leave their friends. Things changed, however, with the arrival of an Imperial probe droid. Han and Chewie engaged it, all but confirming the spy droid was sent by the Empire. When Imperial forces arrived, they made a hasty escape with Leia and C-3PO on the Millennium Falcon and were pursued through an asteroid field.
from – Chewbacca | StarWars.com
Chewbacca with snowy Hoth painting.