A spiral cloud appears just off the southern California coast in this image seen by the Suomi NPP satellite's VIIRS instrument on February 1, 2018. While one might mistake this cloud for a small hurricane, it is actually just a harmless cloud formation known as a von Kármán vortex. Named after Theodore von Kármán, a co-founder of NASA’s Jet Propulsion Laboratory, these stratocumulus clouds form when air moving over a relatively flat surface gets diverted by topographic features, such as an island or a mountaintop. In this image, the vortex formed east of San Clemente Island, about 70 miles off the coast of San Diego. When the prevailing wind was forced to move around the elevated surface of the island, the winds changed direction, causing the clouds to rotate into a spiral shape.
This image was created by combining three of the high resolution thermal and visible channels from the Suomi NPP satellite's VIIRS sensor (SVI 4,2,1). The combination of these channels enhances the contrast between clouds, water, and land surfaces, with the ocean appearing black in this imagery.