In English, uh oh has several shades of meaning, depending on how it's said.
It can indicate a harmless error, such as: "Rats, I made a typo"; it can mean something more vexing, such as: "Oh man, I locked my keys in the car"; or it can be grave, as in: "Crap, by mistake I just sent an e-mail slamming my boss to everyone in the office".
That got me wondering what the Cantonese version would be. I knew that aiyah was the all-purpose term for varying degrees of dismay and was a good match for uh oh in many instances.
But was there another expression? Enquiries led me to daaih wohk (大鑊), or big wok. As slang it means either a disaster or a big mess.

Further research turned up the longer phrase daaih wohk faahn (大鑊飯), or a big wok of rice, which better captures the feeling of a big mess. At one time it referred to the now defunct mainland Chinese system of rewarding workers equally regardless of actual work done, a plan guaranteed to create turmoil.
Over time the diminutive became understood as conveying the more serious sense of uh oh, as in: "That e-mail is going to get me fired", which explains why I hadn't heard it before, or if I had, why it didn't register; I would have thought people were in fact discussing a big wok.
Continued curiosity let me to check if perhaps daaih wohk was used in the Chinese translation of the movie title Big Trouble in Little China, but it wasn't. The actual words, as far as I was able to dig up, translate as Evil Spirits Make a Big Scene in Little Spiritual State, which pretty much describes the plot.
And so another expression has entered my lexicon, though it remains to be seen if I'll ever have occasion to use it.
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