The creek appears to be channelizing in this section. In other words, because of increased stream flow during flooding caused by too much impervious surface in the watershed, the stream is boring downward and leaving cliffs on both sides. The picture below right is a close-up of some of the erosion on the left or west side of the creek. The water is undercutting boulders at this point.
The left photo also shows apparently ripe persimmons in the foreground. However, they were not ready for eating and caused the photographer the classic puckering that persimmons are famous for.
