Describe how the "scablands" of Montana were created.
A giant "ice dam" broke, releasing the water of the very large Lake Missoula. the excelled water created a temporary giant river that was +1000 feet deep and moved at 65 mph. The entire lake emptied in two days. that river "scoured" hundreds of square miles removing topsoil (creating the Scablands) and formed giant sand ripple marks.