Ice Wurm

From an article on GamingNexus:


 * Distant cousins to the sand, chaos, and desert wurms, the great ice wurms are particularly unusual members of the species, making their home in the frigid marches of the Shiverpeaks rather than the warm territories their brethren favor. A thick layer of blubber beneath their tough skin helps insulate them from the cold. These wurms are significantly stronger and more deadly than their southern counterparts, able to burrow through upper layers of stone, as well as dirt or sand. Such abilities, of course, make them much more formidable opponents.

Note: The aticle ommits Frost Wurms (such as Maw the Mountain Heart) who already dwell in the Southern Shiverpeaks.