Ethereal Gravity Wave Clouds Flow over Colorado

I was puttering around on the evening of July 6, 2016, when I got an email from Bad Reader John Kozura: "Go look outside and north at the clouds! Check the waves!" I couldn't see from where I happened to be but I had my camera with me, so I made my way around some trees and turned north. And when my view cleared, what I saw was this: How lovely is that? The Sun had just set and it was getting dark. These long streamers of clouds were low enough to be out of direct sunlight, so they're silhouette...