Lillooet River - 400s BC Eruption of Mount Meager

400s BC Eruption of Mount Meager

The Lillooet River was dammed with breccia from a Plinian style eruption that was erupted from Mount Meager 2400 years ago. The breccia damming the Lillooet River was not very strong, then the water soon eroded the breccia that was damming the river, forming Keyhole Falls. There was a massive flood when the water first broke through the breccia. The flood was big enough that small house sized blocks of breccia were carried away during the flood.