Randall Carlson describes evidence that two of North America’s largest floods may have occurred at the same time. The Bonneville Flood began when a massive Ice Age lake breached its natural dam, releasing water deep enough to carve the Snake River and shape Hells Canyon. According to the research, those waters may have met the floodwaters from Glacial Lake Missoula in what’s now Idaho …a convergence that would have reshaped the landscape on an unimaginable scale.