If you show up without proper identification, you may STILL be allowed to cross the border into Canada, however it might be a longer process. By that, I mean that you would probably have to go in and speak with the immigration officers. It's possible, that by chance, you are not asked for your passport and documentation, it happened to me once... and this was even after a full week in the U.S.
If you want an official answer, you can call the Canada Border Services Border Information Service Line... I take it you are based in the U.S. As is this case, you would want to call:
204-983-3500 (based in Manitoba)
or
506-636-5064 (based in New-Brunswick)
... Pick your poison as far as long distance charges go.
I refer people to these lines every day as part of my job
I can tell you right now that they will give you an "official answer"... but there's always ways around.
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Question re: crossing the border at Niagara Falls
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