About 15,000 years ago during the end of the last Ice Age, a massive ice dam formed in northern Idaho and Montana, creating Glacial Lake Missoula. Over hundreds of years, this ice dam burst and released flood waters, which rushed across Washington and Oregon to the Pacific Ocean. On their way, the floods carved out land features including the Columbia River Gorge and the coulees and scablands of Eastern Washington.

In the Willamette Valley, flood waters rushed in and pooled, creating Lake Allison.

Tualatin lay at the crossroads of these floods in the Valley, affected by the waters coming in then draining out as the floods receded. Around Tualatin you can find examples of the impacts of these floods, including scablands, current ripples, and ice-rafted erratic boulders.

The Tualatin Ice Age Foundation’s mission is to bring awareness of the story of the Ice Age Floods, both locally and throughout the region, as well as to highlight the history of native people who lived and hunted in the area, and the animals (known as megafauna) that existed during that period.