I'm not an expert, but my guess is that you'll be fine if it was just 24 hours. THere are folks that soak various orchids for a while (maybe not quite 24 hours). Also, they could get a torrential rain for 24 hours, and still be ok.
I guess it would depend upon the potting media and how well it will allow air to get to the roots.
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Steve
I'm just hoping not to kill them!