The Heretic’s Flood - The Rocks Don't Lie - page 168

lands lay south of the well-documented extent of glaciers. Or maybe ancient rivers slowly
cut down through normal river erosion, although this could not account for the giant
potholes. One prominent critic carefully described—and then ignored—areas of ten-foot-
high undulating ridges running across the trend of the valley they occurred in, features
Bretz later identified as incontrovertible evidence of catastrophic flooding.
The tide turned at the 1940 Seattle meeting of the American Association for the Ad-
vancement of Science. In a session on the glacial geology of the Pacific Northwest crowded
with megaflood skeptics, Joe Pardee described evidence for giant ripple marks on the bed
of the glacial-age Lake Missoula. Pardee recognized that the fifty-foot-high ripples on the
lakebed were formed by fast-flowing currents rather than the sluggish bottom water of
an impounded lake. Only sudden failure of the glacial dam could have released the two-
thousand-foot-deep lake. Pardee did not need to point out that here was a logical source for
Bretz's flood: the catastrophic release of six hundred cubic miles of water through a narrow
gap would sweep away everything in its path.
In 1952 Bretz returned for a last summer of fieldwork in the scablands. Nearly seventy
years old, he wanted to see evidence uncovered by the Bureau of Reclamation's Columbia
Basin project. He was delighted to find their excavations showed that the hills he inter-
preted as hundred-foot-high gravel bars were indeed formed by deep, fast-flowing water.
Examining the bureau's aerial photography, Bretz found the smoking gun that clinched
his story. The bird's-eye view revealed the rugged rise and fall of the topography he re-
called scrambling over decades before to be giant ripples like those hundreds of miles
upstream at the outlet to Lake Missoula. Hidden beneath the sagebrush, the field of
megaripples was strikingly obvious from the air. There was “no other explanation for their
rhythmic patterns than that of bedform development by amazingly deep, swift flood wa-
ter.” 1 Bretz had been right all along.
It had taken decades, but he finally had the evidence to convince skeptical colleagues. In
August 1965, an international delegation of geologists traveled from Lake Missoula down
through the scablands to see the evidence firsthand. Bretz was no longer able to travel, so
at the end of the trip the delegation sent him a congratulatory telegram that ended with “We