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Mystery of the Megaflood
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Program Overview
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NOVA
presents the story of the greatest flood ever found in the geologic record and
the geologist who went against prevailing theories to explain that the flood
had occurred.
The program:
reviews geologist J Harlen Bretz's radical theory—first proposed in
1923—that a massive flood formed some of the Pacific Northwest's unusual
geologic features. presents the evidence collected by Bretz during his research, including
the existence of the Channeled Scabland and the dry waterfalls, potholes, and
erratics within the scablands. explains that, at the time, most scientists believed the Northwest's
geological features were created through gradual erosive processes; the
scientists followed the theory of uniformitarianism, which ruled out sudden
catastrophic creations of landscapes. recounts the difficulty faced by Bretz as he worked to convince the
scientific community of his theory. reports the key role of Joseph Thomas Pardee, the geologist who found
evidence for an enormous body of glacial meltwater that could have provided the
flood's source of water. describes how Pardee theorized that a lobe of the Cordilleran ice sheet
dammed the Clark Fork River, forming an ice barrier that eventually walled off
a lake described in size as "an inland sea." recreates what might have happened when the lake's water eventually
breached the ice dam, allowing Glacial Lake Missoula to flood westward. reveals evidence indicating that the flood Bretz theorized may have been
only one of many that repeatedly swept through the region.
Taping Rights: Can be used up to one year after the program is taped off the air.
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