A colleague in Page, AZ walked up the lower slope of the Chinle Formation beneath the base of the slump along Highway 89. He did this only three days after it happened and got some really good shots, which he shared with me. It is clear from his pictures that the slump is truly a geologic event as ore than just road metal is involved. See my previous posting here where I postulated that maybe just the backfill in road construction was what failed. However, you will clearly see here that Chinle Formation bedrock also broke away from beneath the road.