Subscribe | UPI Odd Newsletter Subscribe LOFTHOUSE, England, Jan. 30 (UPI) -- Britain's Highways Agency said the violent swaying of lamp posts in a video taken by a motorist driving in high winds was an example of "vortex-shedding." Bob Hill posted a video on YouTube showing lamp posts swaying violently in the wind while he was driving Wednesday on M62 near Lofthouse, England. Advertisement The Highways Agency posted a comment explaining why the posts were swaying while other tall objects in the background, including other lamp posts, didn't move at all. "This video shows 'vortex-shedding' -- when the natural frequency of a lamp column matches the speed of the wind. It only happens at certain wind speeds and is a fairly rare event," the comment read. Read More Wrong turn: British bus makes 140-point turn Belfast residents warned not to eat fish from street spill Sunbathing seal blocks Tasmania highway Cow escapes from moving truck on Russian road