Monday, Sep. 01, 2008

Ice Age floods fascination grows

By John Trumbo, Herald staff writer

There's something about the Ice Age floods story that just blows people away.

That's what happened to Bruce Bjornstad when he first heard about how a massive ice dam gave way in what is now North Idaho, releasing a mountain of water backed up into present Western Montana.

The nearly 200-foot high wall of water, stretching miles wide, took a 200-mile helter-skelter Path across Eastern Washington, grinding and dozing the earth and everything on it.

It's a story 18,000 years old, or perhaps a million years back no one knows for sure but not revealed and understood until the last half-century.

Bjornstad, a geologist with the Pacific Northwest National Laboratory, was doing graduate work in Portland in 1977 when an instructor gave him a pamphlet about the scablands of Washington.

Bjorstad had driven west from his native New Hampshire, wondering as he passed through the scablike landscape of Eastern Washington what could have created that confused scenery.

The pamphlet revealed a theory, first expressed in the 1920s by geologist J

Harlen Bretz, that a massive scouring by immense and swift waters was the only way the Earth could be so horribly hewn and scarred to the bedrock basalt.

That a megaflood did it all was awesome to Bjornstad.

Fellow PNNL employee George Last, who works as a geohydrologist, is equally impressed.

"I never had an 'Aha' moment because I grew up here and knew about Palouse Falls," Last said.

But the sheer scale of the megaflood, which many believe occurred dozens, if not hundreds of times over millennia, has given Last enough "mystery and history" to last his lifetime.

Last specializes in the study of how mammoth remains were deposited during the Ice Age floods, as they have become known. Where the bones came to rest indicates where and how high the flood tides were.

In the Tri-Cities that was 900 feet, leaving only tips of Candy Mountain near Richland and the upper 100 feet of Rattlesnake Mountain as dry land as waters backed up behind Wallula Gap.

Bjornstad spends his off time from the lab studying the placement of other flood debris, particularly boulders called erratics that floated in on icebergs during the floods.

Some of those rocks, weighing several tons each, came from thousands of miles away. Some can be seen on a hike up Badger Mountain where a kiosk along the trail describes the floods.

What began with one geologist's theory decades ago and wasn't fully recognized by Bretz's peers until the 1970s is going mainstream. The flood story started seeping into the public's consciousness about 15 years ago, following a book called Cataclysms on the Columbia by John Allen, said Bjornstad, who has written his own book and has another under way.

Gary Kleinknecht, a history teacher at Kamiakin High School, said the growing public interest spawned the founding of the Ice Age Floods Institute in 1995. It now has eight chapters across the Pacific Northwest, with 80 members alone from the Tri-Cities area who constitute the Lake Lewis Chapter.

"Most of our members are people who have no training in geology. The sheer magnitude of what happened is what makes the story irresistible for most people," said Kleinknecht, who is the current president of the institute. "This really puts you in your place," he said.

The megaflood story has mystery, intrigue and intellectual challenge, Kleinknecht noted.

"There's a real thirst for knowledge on this topic," said Last, who like Bjornstad often spend weekends leading educational tours around the Mid-Columbia.

The daylong tours point out the scablands, and major flood cataracts like Palouse Falls and Dry Falls, each as evidence of the powerful flood hydraulics that pounded out chasms while racing at speeds of 60 to 70 mph toward the Pacific Ocean.

Curiosity about the mystery and history is one thing, but what Last, Bjornstad, Kleinknecht and the institute members really want is for Congress to establish an Ice Age Floods national geologic trail that covers the path of destruction/creation across Montana, Idaho, Washington and Oregon.

"What's exciting is the more questions we can answer the more we realize there is more out there to be discovered about what happened and when it happened," Bjornstad said.

Bjornstad spent three years writing his book, On the Trail of the Ice Age Floods, which is a guidebook to the flood-based geology of the Mid-Columbia Basin. His second book will cover a different area in the four states affected by the flooding.

The megafloods are believed to have occurred when a wall of glacier ice east of present day Sandpoint in Idaho's Panhandle that held back ancient Missoula Lake collapsed, unleashing the deluge. Repeated floods happened when the glacier flow plugged and broke repeated over time.

Aerial views of Eastern Washington reveal floodlike features, such as huge ripples on the sand bar north of Vantage at Trinidad.

Wallua Gap is believed to be where the megaflood eventually flowed out of the Mid-Columbia toward present day Portland.

"If you look at Wallua Gap it is huge, yet it was too small to handle the 10 million cubic meters per second. That is 10 times the combined flow of all the rivers in the world today," Last said.

"Arguably this is probably the last freshwater floods documented on Earth," he said.

This year's annual meeting of the Ice Age Floods Institute will be Sept. 26-27 at Polson, Mont., on the shore of Flathead Lake. Two tour buses with about 90 people will attend from the Tri-Cities, Kleinknecht said.

The organization has members who are available for speaking engagements and field trips for the public's edification, he said.

Membership in the institute is $30 per person or $45 for a family.

For more information about the institute, go to www.iafi.org.