Lake Diablo is at about 1200 ft above sea level in the Cascade Mountains off of Hwy 20. Its beauty, the color of the water set against the trees and mountains, is best seen on a sunny day. It is "rock flour", as it is called, from the glaciers wearing against the mountains that gives the water this color. I had passed it several times when my brother was living in Eastern Washington and I was always waiting for the right sunny days to stop and get a few photos. This is one place I would like to make a trip back to.