Astronauts on the International Space Station had a window seat for one of cloudland’s grand spectacles: von Kármán vortex streets. These spiralling clouds are named after the Hungarian-American physicist and aerospace engineer Theodore von Kármán, who described vortex shedding, the process that sets in motion chains of vortices as a fluid flows around a blunt obstacle. In this case, the flow is of winds around the volcanic peaks of Isla Guadalupe off the coast of Baja California, Mexico.

Obstacles of terrain like Guadalupe can create an oscillating flow of wind vortices that alternate in direction. A vortex cloud street can be ginormous, extending more than 250 miles (400 km) downwind of the feature that caused it. Each swirl might be around 10 to 25 miles (15 to 40 km) across. Since they form in low clouds, such scales mean that von Kármán vortex cloud streets are not visible to cloudspotters at Earth’s surface. But we can hear their equivalents. The same vortex shedding that creates swirls of cloud also causes the harmonic oscillations we hear in a stiff wind as the eerie hum of overhead power lines.