NORTH DAKOTA STATE UNIVERSITY - FARGO, N D
This large slump is located north of Bismarck, at the site of the Double Ditch Indian Village. It was initiated by erosion against this slope by the Missouri River (just out of view to the right on this photo).
In the next photo, we see the progress of this slump over just nine months. (Use the telephone pole and highway as reference points between the two photos).