The weather geek who sent me this photo loves the wind vortices evident in the clouds off the Southern California coast this week. She even says the wind maps after the jump explain why it happens. I just see a nice image, which you can click on to see much bigger. (Side note: Notice how the Colorado River all but disappears as it reaches the lower desert and, eventually, Mexico.)
Wikipedia defines this effect — a von Kármán vortex street — as "a repeating pattern of swirling vortices caused by the unsteady separation of flow of a fluid over bluff bodies. It is...responsible for such phenomena as the 'singing' of suspended telephone or power lines, and the vibration of a car antenna at certain speeds." Here's a UCLA prof's animation of the effect this week, and a local weather scientist's previous admiration for the phenomenon.