The geologic history of my scout camp (Wolfeboro — Stanislaus River CA) is just such an event. The glaciers were from the ice age and they retreated making a lake and then the dam broke and the lake became a sand flat and later a logepole pine forest and finally a tall pine forest and an ideal Scout summer camp. I loved that experience and part of the camp nature was to educate us as to this history. Good for the Scouts BSA.
Starved Rock park in Illinois is suspected of being created by a glacial outburst. I’ve read accounts that the Illinois river used to be the head water of the Mississippi or at least part of the path. The river bluffs along the Illinois river maybe only 10K to 15K years old...