Light rain began blowing against the windshield as I drove south on Interstate 5 towards Weed, California. The sun was still shining, but Mount Shasta was obscured by clouds. I stopped at a rest area to stretch my legs, and looked north, the way I had come: there was a rainbow behind me. As I watched, a faint second rainbow was forming. I took a photo, got back in the car, my hair blown every which way, my glasses speckled with rain drops, and drove south into the rain.