Bretz defended his theories , kicking off an acrimonious 40 year debate over the origin of the Scablands . As he wrote in 1928 , " Ideas without precedent are generally looked upon with disfavor and men are shocked if their conceptions of an orderly world are challenged . " Both Pardee and Bretz continued their research over the next 30 years , collecting and analyzing evidence that eventually identified Lake Missoula as the source of the Spokane Floods and creator of the Channeled Scablands . Research on open channel hydraulics and NASA satellite images in the 1970s further vindicated Bretz 's and Pardee 's theories
Spokane Floods
Missoula Floods
J Harlen Bretz