Board Thread:False Info and Speculative Discussion/@comment-24.130.28.230-20150721180826/@comment-4091815-20160130202152

Had they not been so unequivocal in saying "nothing supernatural can cross" then you would be right. In this case, they gave us a clear landmark in judging the supernatural. Can cross mountain ash, not supernatural. Can't cross mountain, supernatural.

All Banshee seen on the show are able to use and cross mountain ash meaning, by the definition of the show, banshee are not supernatural.

They could have said "shapeshifters can't cross." They could have said "Werewolves and Kanima can't cross." They didn't. They said "nothing supernatural."