This is one end of a long wave cloud, on the lea side of the Rocky Mountains. This day, high level winds were trying to break up the clouds and you can see the start of lenticular clouds and much turbulence in the picture. I wanted to include some ground, but there were some office buildings and towers that were too distracting to my eye, so I shot above the horizon. The camera is pointed North-East, just a few minutes before sunset.
Canon 5D MkIII, with EF 24-105mm f/4L IS at 24mm
Av Mode, ISO 800, +5/3EV, f/11, resulting in 1/160-sec., hand held
Raw conversion with DxO Optics Pro 9.1