A "total cloud inversion" is what they called it; and at first, the visitors to the Canyon were miffed that they didn't get to see, you know, a canyon, rather than the soup bowl this was yesterday. Until they were told it was a kind of rare event. Then they felt special.
But what's really cool is how the soup rose from the bottom up, as this time-lapse (15 to 1) video shows:
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