Image
UK weather conditions left lampposts swaying violently in gale force winds
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.

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.