Monday, Sep. 01, 2008

Backyard Tourist: See results of Ice Age floods north of Moses Lake (w/ video)

By Michelle Dupler, Herald staff writer

Take Highway 17 north from Moses Lake, and the observant driver will start to notice boulders the size of beachballs littering the fields along the road just outside of town.

Keep heading north and the boulders get bigger, until you spot rounded, weathered hunks of rock the size of Volkswagen Beetles in the midst of the craggy terrain.

The boulders are remnants of a series of catastrophic floods that carved and shaped the unique Mid-Columbia landscape known as the Channeled Scablands.

The scablands cover most of Eastern Washington from the edge of the Palouse region in the east to the Columbia River to the west.

They were formed when vast Ice Age lakes spilled over and burst ice dams created by glaciers, and torrential waters rolled across the landscape at up to 80 mph.

The force and speed of the water flowed into the bowl-like Columbia Basin and carved canyons, cataracts, ripples and potholes before hitting a bottleneck at Wallula Gap -- submerging the area now occupied by the Tri-Cities under 900 feet of water known as Lake Lewis, said geologist Bruce Bjornstad.

This happened hundreds or possibly 1,000 times starting 1 million or 2 million years ago and repeated during cooling cycles until the last Ice Age 13,000 years ago, he said.

One of the most impressive features left behind is Dry Falls, a 400-foot-high, 3-mile-wide cataract where flood waters once spilled over the greatest waterfall in the world.

Another is Palouse Falls, where the Palouse River was diverted from its former path toward Pasco over a cataract and eventually into the Snake River at Lyons Ferry.

Stand at the edge of Dry Falls, along Highway 17 about 18 miles north of Soap Lake, and you get a sense of the vastness and ancientness of the landscape.

No water now tumbles over the falls, but Dry Falls once roared mightier than Niagara Falls, which is less than one-third as wide and half as high.

Fences around part of the rim allow visitors to stand and gaze in awe at its magnitude and the remnants of plunge pools below.

A small interpretive center tells the story of the Ice Age floods and includes a gift shop with trinkets and books about the area's geology, wildlife and Native American past. Admission is free.

Palouse Falls State Park doesn't include an interpretive center, but does offer spectacular views of the spot where the river plunges 200 feet.

A quarter-mile hiking trail leads to an observation point along the cataract's rim.

Bjornstad said today's Mid-Columbia residents have reaped numerous benefits from the Ice Age Floods, which carved channels now used for irrigating farm land and deposited the rich, fertile soils that have made the region famous for its wineries and other crops.

* To get to Dry Falls: Take Highway 395 North to Highway 17 North. Stay on Highway 17 through Moses Lake and Soap Lake until you reach the Dry Falls Visitor Interpretive Center, part of Sun Lakes State Park. Distance: 112 miles north of Pasco. Driving time: 2.5 hours.

* To get to Palouse Falls: From Highway 12 East in Pasco, take the Pasco-Kahlotus Road north through Kahlotus to the Highway 260 junction and turn right. Turn right again at Highway 261, then left on Palouse Falls Road about 2 miles east to Palouse Falls State Park. Distance: 63 miles northeast of Pasco. Driving time: 1.5 hours.