Lava + Ice + Water = Floods Geology

Floods of lava (Columbia River Basalts) and Ice Age Floods of water (Lake Missoula floods and the Bonneville Flood) are world-famous topics among geologists. To have both sets of floods in the same area means the geology of the Inland Northwest is truly Disneyland for Geologists!

The program begins in Lewiston, Idaho where the floods of lava and water are beautifully on display near the mouth of Hells Canyon. Early on, the Columbia River Basalts – eruptions of fluid lava from deep fissures – are featured. The Missoula Floods from Montana and the Bonneville Flood from Utah – the Ice Age Floods – are surveyed at an introductory level. And finally, the interaction between bedrock and fluid dynamics of the floodwater are highlighted through discussion of Ice Age erosional and depositional landforms. Key locations in the Pacific Northwest are featured, including the Snake River Canyon, Grand Coulee, Dry Falls, the Drumheller Channels, Wallula Gap, and the Columbia River Gorge.

Tom Foster ( and Nick Zentner (Central Washington University) have been hiking together in eastern Washington for years. The result? A series of short videos that showcase geological wonders in the Pacific Northwest. This 16-minute video – Huge Floods in the Pacific Northwest – offers an introductory overview of spectacular geologic events that impacted much of Washington, Oregon, and Idaho.

More than a dozen “2 Minute Geology” episodes are now available online at

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