Tracking route of catastrophic ice-age floods


WASHINGTON — Congress is reviving legislation to create a trail
that would trace the route of catastrophic ice-age floods that left
scars across the Pacific Northwest.

Visitors could drive the 600-mile trail and stop at interpretive
centers and roadside pullouts to learn about the floods that were
unleashed when an ice dam in what's now Montana collapsed, draining a
lake the combined size of Lake Erie and Lake Ontario in two days.

The trail would cost $8 million to $12 million to create, and the
National Park Service would oversee it.

The Senate Energy and Natural Resources Committee approved the
measure Wednesday.

``The size and scope of what happened here is hard to fathom,''
Sen. Maria Cantwell, D-Wash., the prime sponsor of the bill, said of
the floods. ``This is one of the most unique events in the geologic
history of the Earth. We usually see things like this on other

Similar legislation cleared the Senate last year but died when the
session ended before differences with the version that the House
passed could be resolved. Cantwell said she expects the measure to
pass Congress this year.

``We seem more in sync,'' she said, adding that the trail would
boost tourism and economic development in nearby communities, in
addition to explaining a major geologic event.

The floods occurred 13,000 to 18,000 years ago during the last
major ice-sheet expansion.

The ice dam that blocked the Clark Fork River near what's now Lake
Pend Oreille failed repeatedly. At its largest, Glacial Lake Missoula,
as it's now known, was more than 2,000 feet deep and held more than
500 cubic miles of water, according to the Ice Age Floods Institute, a
group from Richland, Wash., that has extensively studied the floods.

During the worst of the floods, a wall of water shook the ground as
it swept down the Columbia River drainage across parts of Montana,
Idaho and Washington.
After passing through the Columbia River Gorge, the flood backed up
into Oregon's Willamette Valley, covering the Portland area with 300
feet of water and reaching as far south as Eugene.

Sediment from the flood has been found in the Pacific Ocean
hundreds of miles from the mouth of the Columbia River.

The floods redistributed more than 50 cubic miles of earth and
rock, creating coulees, buttes, boulder fields, lakes, ridges and
gravel bars that remain today.

The floods provided much of the fertile soil that's found in the
Willamette Valley and left behind the 189-foot Palouse Falls in
Eastern Washington as well as Dry Falls, which has a rim 10 times that
of Niagara Falls.

``There is no doubt this is worthy of recognition and notice,''
Cantwell said.

Rep. Doc Hastings, R-Wash., is sponsoring the House bill.

(Distributed by Scripps Howard News Service.)