[RedwM]

I saw a documentary that theorised that a huge glacial ice dam busted and created the Grand Canyon.

[cripplecreek]

I was watching a show today about the Channeled Scablands. Scientists believe it only took some 48 to 72 hours to created them after the breaking of an ice dam.



They think the flow was equal to the combined output of every river on the planet times 10,000.