"Extraordinary and beautiful examples of toroidal vortices produced by dolphins, beluga whales, humpback whales, volcanoes, hydrogen bombs, and man.
Thrive Movie (in depth look at the true power and relevance of the natural toroidal shape):
http://www.youtube.com/user/ThriveMovement
http://thrivemovement.com/ "
Helicopters, microbursts, breaching cetaceans, lots of things cause toroidal vorticis flow in fluids
http://en.wikipedia.org/wiki/Vortex_ring