Whoa there!

Which is correct: 'whoa' or 'woah'? Many would pick the latter, or be unsure as to which to choose. Many, when typing, enter the latter without thought. However, that is a mistake, for 'woah' is not actually a word. The correct spelling is 'whoa' - which uses the common 'wh' that is found at the beginning of so many words (which, what, why, where, etc). I'm at a loss as to why this mistake has become so prevalent, for it has no logical basis such as that found in the misspelling of 'lose' for example. Furthermore, 'woah' should look wrong to the reader, as it would clearly be pronounced with two syllables as WO-AH rather than merely the one syllable WO. This is one of those mistakes that makes the writer look very foolish, and cannot be passed off as merely a 'typo.'