"It was the biggest flood in the world for which there is
geological evidence," writes Norman Maclean in
A River Runs Through It, referring to the catastrophic
deluge that tore through the Pacific Northwest every time
Glacial Lake Missoula's ice dam gave way. "[I]t was so vast a
geological event that the mind of man could only conceive of
it but could not prove it until photographs could be taken
from Earth satellites." Proof now in hand, geologists today
point to numerous features in the landscape that reveal the
extreme scale and violence involved in these truly colossal
floods. In this interactive map of the vast region affected,
both within the storied Channeled Scabland and beyond, take a
look at some of these telling features. To launch the
interactive, click on the image at left.—Peter Tyson
