As the recent commenter noted, nikk has an entry for this as an abbreviation, pointing to 「板裏草履」 aka 「板草履」, meaning a thonged sandal with a piece of wood under it. The reverso snowboard sentences seem to be 板+裏.

No references have been forthcoming supporting the submitted meanings (copied from 「裏板」).

seems just like a variant of "裏板", which already has an entry
nikk also has an entry for "板裏" which seems to mean wooden zouri

Needs reference(s). Reverso has some sentences where it refers to the back of a snowboard.

Google N-gram Corpus Counts
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│ 板裏 │ 3,122 │
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