Solving the mystery of a dinosaur mass grave at the 'River of Death'

[nitpicked]

https://www.bbc.com/news/articles/c0k3x8lmje1o

Hidden beneath the slopes of a lush forest in Alberta, Canada, is a mass grave on a monumental scale.

Thousands of dinosaurs were buried here, killed in an instant on a day of utter devastation.

Now, a group of palaeontologists have come to Pipestone Creek - appropriately nicknamed the "River of Death" - to help solve a 72-million-year-old enigma: how did they die?
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All the evidence suggests that this catastrophic event was a flash flood - perhaps a storm over the mountains that sent an unstoppable torrent of water towards the herd, ripping trees from their roots and shifting boulders.
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