Travel Journal: Palouse Falls, WA, 2021-05-13.
A massive flood created Palouse Falls in western Washington State when a half-mile high dam of ice holding back glacial Lake Missoula broke (and it broke many times) more than 13,000 years ago. The flood(s) sent billions of tons of water raging across western Washington. Now the Palouse River pours over a basalt precipice and makes for pleasant cliffside viewing. We know the history because geologists studied and determined the cause. Wherever we’re at, that place has a history.
— source: “Washington State Parks, Palouse Falls State Park flyer, a information posters at the park.