It has to do with kyurem the legendary ice/dragon type
Because Kyurem covered half of it in ice. For what reason it is not known as it happened during the two years that separate Black/White from Black/White 2. It might be revealed later but as of now nobody could tell you except gamefreak.
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covered half of it in ice. For what reason it is not known as it happened during the two years that separate Black/White from Black/White 2. It might be revealed later but as of now nobody could tell you except gamefreak.