You’ve probably seen many references to “tsunamis, often incorrectly referred to as ‘tidal waves.'” Claire at Anggarrgoon points out that this is an odd thing to be persnickety about:
I’m not sure why people eschew opacity in this particular compound; there are plenty of phrases and compounds with tenuous relationships to their components. Bowl and board, for instance, has little to do with planks of wood (but was less opaque when “board” meant “table”), bridegrooms have nothing to do with horses, and never have done, koala bears aren’t bears but try telling a marketing manager that, etc etc.
(But what is “bowl and board”?)
Addendum. I just heard an expert interviewed on NPR refer to “the tidal wave.”