From the USGS:
As air flows over and around objects in its path, spiraling eddies, known as Von Karman vortices, may form. The vortices in this image were created when prevailing winds sweeping east across the northern Pacific Ocean encountered Alaska's Aleutian Islands.
More images from Landsat-7 here.
Image courtesy of USGS National Center for EROS and NASA Landsat Project Science Office