A Closer Look at Eastern Washington’s Rock Lake Area

Legends claim a giant serpent once tore up canoes and killed Native Americans in Rock Lake, near St. John. Or maybe we can chalk the tales up to cold water, 300-foot cliffs and submerged rock shards. But whether or not a Nessie haunts its depths, Eastern Washington’s largest natural lake still remains a spectacular example of the area’s unique geology.

Geologic History

During the last Ice Age, the Clark Fork River backed up behind a 2,000-foot dam of frozen water. Periodically, it would splinter and hurtle the inland sea toward the Pacific. Reaching 65 miles per hour, these floods scoured away soil, gouged lakes and canyons and exposed ancient lava flows that had cooled into many-faceted basalt columns. While visible throughout the region, these geometrical features really shine at the Drumheller Channels, a national natural monument 6-miles northeast of Othello.

Yet the ice sheets also replenished the region. Fine dirt—made from glacial flour, volcanic ash and floodplain silt—collected on their edges. The wind then swept it into dunes, often steep on the north and gently sloping on the south.

Such sculpting shows vibrantly in the Palouse, where this fertile soil can stack hundreds of feet deep alongside scraped-clean buttes and basins known as “the Channeled Scablands.”

These areas have a stark beauty—one now being celebrated by the Ice Age Floods Geologic Trail, a first for the U.S. This emerging network of road-trip routes will soon connect landmarks and interpretive centers.

Things to Do

Visitors can roll through the rich, undulating farmland between Colfax and Pomeroy, where spotted horses peer from cherry-red barns among fields of rye, wheat and golden canola. Then check out the craggy glory of the 198-foot Palouse Falls and other landmarks carved by the floods, like the deep, dramatic chasm of the Devils Canyon near Washtucna.

Learn more about Palouse Falls and other attractions in the area.

— Amanda Castleman