The Turgon Exodus came about during the Phael-Tetramord War (10 - 25). In this conflict the war turned for the worse when a rift to the Abyss was made permanent. This inter-system rift, the Ungorth Reddik Road, resulted in thousands of demons coming to Turgon.
The elves of the Phael alliance were forced to leave the continent by all available means. Most went by ships, while others left by magic, or make-shift craft. Most of the elven peoples went north across Mephigax and settled in the region High Wood Country. A smaller group, those of Celanil, sailed east across the great oceans and settled in the lands of Pipe Home.