The Canary Islands' vortex streets

The seven Canary Islands lie off Morocco in the north-east trade wind. Each of the tall ones can shed its own street, so a single photograph can hold several side by side.

What the satellite saw

Rows of cloud eddies trailing south-west from the Canary Islands and Madeira toward the open Atlantic
The Canary Islands, 20 May 2015: three separate streets of eddies in one frame, Madeira's at the top. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response ("Canary Islands Kick Up Von Kármán Vortices"). Public domain.
The wake behind Canary Islands as Wind Tunnel draws it, the NASA photo of the real one laid over the lower right corner
Canary Islands in Wind Tunnel with Satellite photo on: the simulation, made in your browser, with NASA's photo in the corner.

NASA's Terra satellite photographed them with MODIS on 20 May 2015 (Earth Observatory, "Canary Islands Kick Up Von Kármán Vortices"). NASA points out three distinct streams of eddies in the one frame; Madeira's is at the top.

Why the Canaries

Height. Teide on Tenerife rises to 3,715 m, the highest peak in Spain; La Palma, Gran Canaria and La Gomera are tall too. The trade-wind cloud sits far below their tops.

The trade wind. It blows from the north-east most of the year, steady in strength and bearing.

Spacing. The islands sit far enough apart that each wake forms before it meets the next, which you can try in the tunnel by drawing a second island downwind.

Make it in Wind Tunnel

  1. Open the link below, or press Canary Islands under Island: the wind starts from 30°, north-north-east.
  2. Press Cloud under Look and Satellite under Colour: white cloud on a blue-grey sea, as the photo sees it.
  3. Turn on Satellite photo under Island to lay this photo over the corner of the frame, beside the flow.
  4. Press Vorticity under Look to tell the streets apart by their spin.

Open Canary Islands in Wind Tunnel