 At the end of the last ice age approximately 10,000 years ago, massive floods from the melting glacial ice carved deep canyons into the underlying plateau-capping lava flows.Most of these canyons contain rivers such as the Murtle and Clearwater, and waterfalls such as Canim Falls, Moul Falls, Spahats Falls and the high Helmcken Falls.The faces of the basaltic lava flows and waterfalls remain vertical due to the nature of the basaltic lava flows.