Made by moving the camera (intentionally) during a longish exposure (1 sec by stopping down to f/36). Freeman Patterson, one of my favorite photographers, popularized this technique. It's something that I've never gotten the hang of. I look at this type of image done by others and think - That's really nice - and then do one myself and can't repeat what I think. I posted this one just as a reminder to keep trying.
Going on a once in a lifetime trip through the western national parks soon. I've challenged myself to come back with some images that I couldn't get just by buying a postcard. Techniques like camera movement, montages (image overlay) and multiple exposures are on the list of things to try. I'm comfortable with the latter two, but not movement. Keep practicing; time is running out.