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No, it's not Santa's beard. It's a von Karman vortex, of course, as seen from space.
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Insects get a boost from von Karman vortices. See below
Santa's Beard? Actually, it's a vortex street. North is to the left. | 
Animation: How a vortex street develops behind a cylinder moving through fluid. | | More vortices | 
The SeaWifS satellite also spotted a von Karman vortex around Guadalupe Island, back on August 20, 1999. | Animation courtesy of Cesareo de la Rosa Siqueira at the University of Sao Paulo, Brazil Bee illustration 2000 www.arttoday.com
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What? You don't believe in von Karman vortices? Well, let us try to convince you.
These strange cloud formations form in the wake of giant obstacles on Earth, in this case the 4,300-foot- (1.3-kilometer-) high volcanic island of Guadalupe, west of Baja California in the Pacific Ocean. The picture, released last week, was taken by the Multi-angle Imaging SpectroRadiometer (MISR) camera aboard the orbiting Terra spacecraft.
As wind blows from the northwest to southeast (the lower left to upper right in the click-to-enlarge image) it runs into the island and gets spun into vortices, similar to the eddies that form when a receding ocean wave curls around your ankles.
Clouds make the vortices visible. The center of each vortex is clear, researchers say, because the rotating motions cause some wind to blow vertically, breaking up the otherwise solid deck of clouds.
"Karman vortex streets are very common," said Ralph Kahn of NASA's Jet Propulsion Laboratory, which operates the satellite. "Conditions that make them easily visible from space, such as the stratocumulus cloud field in the MISR image, are fairly common as well."
- Kahn said cloud formations like von Karman vortices, which have been well understood since the early part of this century, can help scientists study weather on other planets, where researchers can't take direct measurements. Scientists have long studied the swirling clouds of Jupiter for clues to what's going on deeper inside the shrouded giant.
- Leonardo da Vinci,
von Karman, and bugs
The phenomenon is named after Theodore von Karman, a Caltech professor from 1930 to 1949 and one of founders of the Jet Propulsion Laboratory who first described the phenomenon in the atmosphere.
And, as von Karman knew, vortex streets wind through more than just layers of clouds. He studied their movement in fluids. The vortices are formed as pressure differences, created by the obstacle, force some of the fluid (or air) to move more quickly than the rest (see click-to-enlarge animation).
In fact the curly shapes have been known for centuries. Leonardo da Vinci long ago sketched a row of vortices forming behind a piling in a stream.
And recent studies show that insects borrow energy from the vortices that form around their wings during flight. Normally vortices just create drag. But insects can recapture some of their energy, scientists say, and use it to improve speed and maneuverability.
Insects learn to rotate their wings before starting the return stroke, and the wings are lifted by the eddies of air created on the downstroke.
Click here to see more images of Earth from space.
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