The Snow Sea was an area in Icereach prior to the Cataclysm that was held back by the Ice Wall. Each year the King of Icereach would use the Axe of Gonnas to break the wall and release the sea and the Sturmfrost upon the land. After the Cataclysm it seems Icereach is in perpetual winter, so it is assumed the Ice Wall no longer holds it back.
References[]
- The Messenger (novel), p. 81