From the announcement:
Mountains of Madness, the new side board expansion for Eldritch Horror, is now available at your local retailer!
A Misktaonic University expedition to Antarctica has discovered prehistoric ruins and encountered inhuman, bloodthirsty creatures. In Mountains of Madness, investigators follow that expedition's trail and search Antarctica’s icy expanses for the clues needed to save humanity from the awakening Ancient Ones. In addition to the side board depicting locations throughout Antarctica, this expansion features two Ancient Ones and eight investigators who are willing to sacrifice their lives and their sanity to save the human race. These brave souls are aided by plenty of new Assets, Spells, and Artifacts as they search for clues and battle not only monsters, but harsh and deadly conditions across the globe.