Holy cow! Check it out -- it's a rainbow at night! There's some random guy walking with a headlamp at the bottom, and then a rainbow above the mountains. It was too faint to see naked-eye, but it randomly turned up in the image afterwards. Sure enough, the (full) moon was rising from the east...
I tried to take a few more pictures of it, but it must have vanished quickly. It is visible (just barely) in the previous image, and even more faintly visible in the curent image is a double rainbow (needs a bit of a contrast stretch).