It was not that she had never had premonitory glimpses of such an outbreak; but rather because, here and there throughout the three months, the surface of life had shown such ominous cracks and vapours that her fears had always been on the alert for an upheaval.
There are no more uses of "upheaval" in the book.
Show samples from other sources
They’d caused such an upheaval in my life …. and I was so glad they did.
Kiera Cass -- The Heir
Stupid, she thought, so stupid of her to think he’d come only for her, that it hadn’t been part of something larger, that he hadn’t wanted more, more destruction, more terror, more upheaval.