It is the flood waters rushing through the canyon that swirl and erode the sandstone. During the monsoon season the most sculpting takes place. During just rainy days the bottom sand becomes deeper and is washed away again during the monsoon.
The size of the canyon walls are easy to see by comparing the size of the people at the bottom. Inside the top area is many feet higher.
Our guide was great. She told us all what to set our cameras on to get the best light and pointed out the best photo angles. You can see the results.
There are two tiny people in the bottom left area.
