Islands that shed vortex streets

Downwind of some islands the clouds curl into two staggered rows of eddies, the von Kármán vortex street. Satellites photograph the same few islands again and again. Each page here shows NASA's photograph, says why that island makes a street, and opens the same flow in Wind Tunnel.

What they share: a peak taller than the low cloud deck, a lid of warmer air above it that keeps the air going around rather than over, and a wind that holds its bearing for days.

1. GuadalupeOff Baja California: the best-known street of all.
2. JejuSouth Korea: the winter monsoon over Hallasan.
3. Canary IslandsSeven islands, several streets at once.
4. Heard IslandSouthern Ocean: one peak above the cloud.
5. Juan FernándezOff Chile: Alejandro Selkirk and its neighbour.
6. MadeiraThe Atlantic trade wind, two great eddies.
7. SocotraArabian Sea: a wake drawn in dust.
8. Cape VerdeFogo and Santo Antão in the trade wind.
9. Sri LankaWhere the tunnel opens: the south-west monsoon.
10. RishiriOff Hokkaido, from the Space Shuttle.

The photographs are NASA's and in the public domain; each page gives its credit line. The coastlines in the tunnel are from Natural Earth.